diff --git a/README.md b/README.md
index 54ceb98..8421e7a 100644
--- a/README.md
+++ b/README.md
@@ -30,8 +30,8 @@ This repository includes [TOMLMojo](https://github.com/forfudan/decimojo/tree/ma
 | ------------ | ------- | ------------------------------------ | ----------------------------------- |
 | `BigUInt`    | `BUInt` | arbitrary-precision unsigned integer | `List[UInt32]`                      |
 | `BigInt`     | `BInt`  | arbitrary-precision integer          | `BigUInt`, `Bool`                   |
-| `Decimal`    | `Dec`   | 128-bit fixed-precision decimal      | `UInt32`,`UInt32`,`UInt32`,`UInt32` |
 | `BigDecimal` | `BDec`  | arbitrary-precision decimal          | `BigUInt`, `Int`, `Bool`            |
+| `Decimal`    | `Dec`   | 128-bit fixed-precision decimal      | `UInt32`,`UInt32`,`UInt32`,`UInt32` |
 
 ## Installation
 
@@ -39,7 +39,7 @@ DeciMojo is available in the [modular-community](https://repo.prefix.dev/modular
 
 From the `pixi` CLI, simply run ```pixi add decimojo```. This fetches the latest version and makes it immediately available for import.
 
-For projects with a `mojoproject.toml`file, add the dependency ```decimojo = ">=0.3.1"```. Then run `pixi install` to download and install the package.
+For projects with a `mojoproject.toml`file, add the dependency ```decimojo = "==0.4.0"```. Then run `pixi install` to download and install the package.
 
 For the latest development version, clone the [GitHub repository](https://github.com/forfudan/decimojo) and build the package locally.
 
@@ -49,6 +49,7 @@ For the latest development version, clone the [GitHub repository](https://github
 | v0.2.0     | ==25.2        | magic           |
 | v0.3.0     | ==25.2        | magic           |
 | v0.3.1     | >=25.2, <25.4 | pixi            |
+| v0.4.0     | ==25.4        | pixi            |
 
 ## Quick start
 
@@ -217,7 +218,7 @@ If you find DeciMojo useful for your research, consider listing it in your citat
     year         = {2025},
     title        = {An arbitrary-precision decimal and integer mathematics library for Mojo},
     url          = {https://github.com/forfudan/decimojo},
-    version      = {0.3.1},
+    version      = {0.4.0},
     note         = {Computer Software}
 }
 ```
diff --git a/benches/bigdecimal/bench_bigdecimal_add.mojo b/benches/bigdecimal/bench_bigdecimal_add.mojo
index 6d28aa4..2ae4751 100644
--- a/benches/bigdecimal/bench_bigdecimal_add.mojo
+++ b/benches/bigdecimal/bench_bigdecimal_add.mojo
@@ -28,7 +28,9 @@ fn open_log_file() raises -> PythonObject:
 
     # Generate a timestamp for the filename
     var timestamp = String(datetime.datetime.now().isoformat())
-    var log_filename = log_dir + "/benchmark_bigdecimal_add_" + timestamp + ".log"
+    var log_filename = (
+        log_dir + "/benchmark_bigdecimal_add_" + timestamp + ".log"
+    )
 
     print("Saving benchmark results to:", log_filename)
     return python.open(log_filename, "w")
diff --git a/benches/bigdecimal/bench_bigdecimal_divide.mojo b/benches/bigdecimal/bench_bigdecimal_divide.mojo
index 5c01e88..399255d 100644
--- a/benches/bigdecimal/bench_bigdecimal_divide.mojo
+++ b/benches/bigdecimal/bench_bigdecimal_divide.mojo
@@ -28,7 +28,9 @@ fn open_log_file() raises -> PythonObject:
 
     # Generate a timestamp for the filename
     var timestamp = String(datetime.datetime.now().isoformat())
-    var log_filename = log_dir + "/benchmark_bigdecimal_divide_" + timestamp + ".log"
+    var log_filename = (
+        log_dir + "/benchmark_bigdecimal_divide_" + timestamp + ".log"
+    )
 
     print("Saving benchmark results to:", log_filename)
     return python.open(log_filename, "w")
diff --git a/benches/bigdecimal/bench_bigdecimal_exp.mojo b/benches/bigdecimal/bench_bigdecimal_exp.mojo
index 7104e3c..fef8cf9 100644
--- a/benches/bigdecimal/bench_bigdecimal_exp.mojo
+++ b/benches/bigdecimal/bench_bigdecimal_exp.mojo
@@ -28,7 +28,9 @@ fn open_log_file() raises -> PythonObject:
 
     # Generate a timestamp for the filename
     var timestamp = String(datetime.datetime.now().isoformat())
-    var log_filename = log_dir + "/benchmark_bigdecimal_exp_" + timestamp + ".log"
+    var log_filename = (
+        log_dir + "/benchmark_bigdecimal_exp_" + timestamp + ".log"
+    )
 
     print("Saving benchmark results to:", log_filename)
     return python.open(log_filename, "w")
diff --git a/benches/bigdecimal/bench_bigdecimal_ln.mojo b/benches/bigdecimal/bench_bigdecimal_ln.mojo
index 79d738c..8d3f20d 100644
--- a/benches/bigdecimal/bench_bigdecimal_ln.mojo
+++ b/benches/bigdecimal/bench_bigdecimal_ln.mojo
@@ -28,7 +28,9 @@ fn open_log_file() raises -> PythonObject:
 
     # Generate a timestamp for the filename
     var timestamp = String(datetime.datetime.now().isoformat())
-    var log_filename = log_dir + "/benchmark_bigdecimal_ln_" + timestamp + ".log"
+    var log_filename = (
+        log_dir + "/benchmark_bigdecimal_ln_" + timestamp + ".log"
+    )
 
     print("Saving benchmark results to:", log_filename)
     return python.open(log_filename, "w")
diff --git a/benches/bigdecimal/bench_bigdecimal_multiply.mojo b/benches/bigdecimal/bench_bigdecimal_multiply.mojo
index 36ce00e..5afa303 100644
--- a/benches/bigdecimal/bench_bigdecimal_multiply.mojo
+++ b/benches/bigdecimal/bench_bigdecimal_multiply.mojo
@@ -28,7 +28,9 @@ fn open_log_file() raises -> PythonObject:
 
     # Generate a timestamp for the filename
     var timestamp = String(datetime.datetime.now().isoformat())
-    var log_filename = log_dir + "/benchmark_bigdecimal_multiply_" + timestamp + ".log"
+    var log_filename = (
+        log_dir + "/benchmark_bigdecimal_multiply_" + timestamp + ".log"
+    )
 
     print("Saving benchmark results to:", log_filename)
     return python.open(log_filename, "w")
diff --git a/benches/bigdecimal/bench_bigdecimal_root.mojo b/benches/bigdecimal/bench_bigdecimal_root.mojo
index 5b5b727..1f5270b 100644
--- a/benches/bigdecimal/bench_bigdecimal_root.mojo
+++ b/benches/bigdecimal/bench_bigdecimal_root.mojo
@@ -28,7 +28,9 @@ fn open_log_file() raises -> PythonObject:
 
     # Generate a timestamp for the filename
     var timestamp = String(datetime.datetime.now().isoformat())
-    var log_filename = log_dir + "/benchmark_bigdecimal_root_" + timestamp + ".log"
+    var log_filename = (
+        log_dir + "/benchmark_bigdecimal_root_" + timestamp + ".log"
+    )
 
     print("Saving benchmark results to:", log_filename)
     return python.open(log_filename, "w")
diff --git a/benches/bigdecimal/bench_bigdecimal_round.mojo b/benches/bigdecimal/bench_bigdecimal_round.mojo
index e184173..b73a53c 100644
--- a/benches/bigdecimal/bench_bigdecimal_round.mojo
+++ b/benches/bigdecimal/bench_bigdecimal_round.mojo
@@ -28,7 +28,9 @@ fn open_log_file() raises -> PythonObject:
 
     # Generate a timestamp for the filename
     var timestamp = String(datetime.datetime.now().isoformat())
-    var log_filename = log_dir + "/benchmark_bigdecimal_round_" + timestamp + ".log"
+    var log_filename = (
+        log_dir + "/benchmark_bigdecimal_round_" + timestamp + ".log"
+    )
 
     print("Saving benchmark results to:", log_filename)
     return python.open(log_filename, "w")
diff --git a/benches/bigdecimal/bench_bigdecimal_scale_up_by_power_of_10.mojo b/benches/bigdecimal/bench_bigdecimal_scale_up_by_power_of_10.mojo
index 2637738..19f6eda 100644
--- a/benches/bigdecimal/bench_bigdecimal_scale_up_by_power_of_10.mojo
+++ b/benches/bigdecimal/bench_bigdecimal_scale_up_by_power_of_10.mojo
@@ -26,7 +26,9 @@ fn open_log_file() raises -> PythonObject:
 
     # Generate a timestamp for the filename
     var timestamp = String(datetime.datetime.now().isoformat())
-    var log_filename = log_dir + "/benchmark_biguint_scale_up_" + timestamp + ".log"
+    var log_filename = (
+        log_dir + "/benchmark_biguint_scale_up_" + timestamp + ".log"
+    )
 
     print("Saving benchmark results to:", log_filename)
     return python.open(log_filename, "w")
diff --git a/benches/bigdecimal/bench_bigdecimal_sqrt.mojo b/benches/bigdecimal/bench_bigdecimal_sqrt.mojo
index 92a2004..3872ac3 100644
--- a/benches/bigdecimal/bench_bigdecimal_sqrt.mojo
+++ b/benches/bigdecimal/bench_bigdecimal_sqrt.mojo
@@ -28,7 +28,9 @@ fn open_log_file() raises -> PythonObject:
 
     # Generate a timestamp for the filename
     var timestamp = String(datetime.datetime.now().isoformat())
-    var log_filename = log_dir + "/benchmark_bigdecimal_sqrt_" + timestamp + ".log"
+    var log_filename = (
+        log_dir + "/benchmark_bigdecimal_sqrt_" + timestamp + ".log"
+    )
 
     print("Saving benchmark results to:", log_filename)
     return python.open(log_filename, "w")
diff --git a/benches/bigdecimal/bench_bigdecimal_subtract.mojo b/benches/bigdecimal/bench_bigdecimal_subtract.mojo
index 1ea8468..bc42695 100644
--- a/benches/bigdecimal/bench_bigdecimal_subtract.mojo
+++ b/benches/bigdecimal/bench_bigdecimal_subtract.mojo
@@ -28,7 +28,9 @@ fn open_log_file() raises -> PythonObject:
 
     # Generate a timestamp for the filename
     var timestamp = String(datetime.datetime.now().isoformat())
-    var log_filename = log_dir + "/benchmark_bigdecimal_subtract_" + timestamp + ".log"
+    var log_filename = (
+        log_dir + "/benchmark_bigdecimal_subtract_" + timestamp + ".log"
+    )
 
     print("Saving benchmark results to:", log_filename)
     return python.open(log_filename, "w")
diff --git a/benches/bigdecimal/bench_scale_up_by_power_of_10.mojo b/benches/bigdecimal/bench_scale_up_by_power_of_10.mojo
index 2637738..19f6eda 100644
--- a/benches/bigdecimal/bench_scale_up_by_power_of_10.mojo
+++ b/benches/bigdecimal/bench_scale_up_by_power_of_10.mojo
@@ -26,7 +26,9 @@ fn open_log_file() raises -> PythonObject:
 
     # Generate a timestamp for the filename
     var timestamp = String(datetime.datetime.now().isoformat())
-    var log_filename = log_dir + "/benchmark_biguint_scale_up_" + timestamp + ".log"
+    var log_filename = (
+        log_dir + "/benchmark_biguint_scale_up_" + timestamp + ".log"
+    )
 
     print("Saving benchmark results to:", log_filename)
     return python.open(log_filename, "w")
diff --git a/benches/bigint/bench_bigint_floor_divide.mojo b/benches/bigint/bench_bigint_floor_divide.mojo
index 6384f66..71186ba 100644
--- a/benches/bigint/bench_bigint_floor_divide.mojo
+++ b/benches/bigint/bench_bigint_floor_divide.mojo
@@ -29,7 +29,9 @@ fn open_log_file() raises -> PythonObject:
 
     # Generate a timestamp for the filename
     var timestamp = String(datetime.datetime.now().isoformat())
-    var log_filename = log_dir + "/benchmark_bigint_floor_divide_" + timestamp + ".log"
+    var log_filename = (
+        log_dir + "/benchmark_bigint_floor_divide_" + timestamp + ".log"
+    )
 
     print("Saving benchmark results to:", log_filename)
     return python.open(log_filename, "w")
diff --git a/benches/bigint/bench_bigint_multiply.mojo b/benches/bigint/bench_bigint_multiply.mojo
index 88c393d..e2bba66 100644
--- a/benches/bigint/bench_bigint_multiply.mojo
+++ b/benches/bigint/bench_bigint_multiply.mojo
@@ -29,7 +29,9 @@ fn open_log_file() raises -> PythonObject:
 
     # Generate a timestamp for the filename
     var timestamp = String(datetime.datetime.now().isoformat())
-    var log_filename = log_dir + "/benchmark_bigint_multiply_" + timestamp + ".log"
+    var log_filename = (
+        log_dir + "/benchmark_bigint_multiply_" + timestamp + ".log"
+    )
 
     print("Saving benchmark results to:", log_filename)
     return python.open(log_filename, "w")
diff --git a/benches/bigint/bench_bigint_truncate_divide.mojo b/benches/bigint/bench_bigint_truncate_divide.mojo
index 369559a..4922218 100644
--- a/benches/bigint/bench_bigint_truncate_divide.mojo
+++ b/benches/bigint/bench_bigint_truncate_divide.mojo
@@ -29,7 +29,9 @@ fn open_log_file() raises -> PythonObject:
 
     # Generate a timestamp for the filename
     var timestamp = String(datetime.datetime.now().isoformat())
-    var log_filename = log_dir + "/benchmark_bigint_truncate_divide_" + timestamp + ".log"
+    var log_filename = (
+        log_dir + "/benchmark_bigint_truncate_divide_" + timestamp + ".log"
+    )
 
     print("Saving benchmark results to:", log_filename)
     return python.open(log_filename, "w")
diff --git a/benches/biguint/bench_biguint_from_string.mojo b/benches/biguint/bench_biguint_from_string.mojo
index 514df64..d30f02e 100644
--- a/benches/biguint/bench_biguint_from_string.mojo
+++ b/benches/biguint/bench_biguint_from_string.mojo
@@ -29,7 +29,9 @@ fn open_log_file() raises -> PythonObject:
 
     # Generate a timestamp for the filename
     var timestamp = String(datetime.datetime.now().isoformat())
-    var log_filename = log_dir + "/benchmark_biguint_from_string_" + timestamp + ".log"
+    var log_filename = (
+        log_dir + "/benchmark_biguint_from_string_" + timestamp + ".log"
+    )
 
     print("Saving benchmark results to:", log_filename)
     return python.open(log_filename, "w")
diff --git a/benches/biguint/bench_biguint_multiply.mojo b/benches/biguint/bench_biguint_multiply.mojo
index 6d50884..38baa94 100644
--- a/benches/biguint/bench_biguint_multiply.mojo
+++ b/benches/biguint/bench_biguint_multiply.mojo
@@ -29,7 +29,9 @@ fn open_log_file() raises -> PythonObject:
 
     # Generate a timestamp for the filename
     var timestamp = String(datetime.datetime.now().isoformat())
-    var log_filename = log_dir + "/benchmark_biguint_multiply_" + timestamp + ".log"
+    var log_filename = (
+        log_dir + "/benchmark_biguint_multiply_" + timestamp + ".log"
+    )
 
     print("Saving benchmark results to:", log_filename)
     return python.open(log_filename, "w")
diff --git a/benches/biguint/bench_biguint_truncate_divide.mojo b/benches/biguint/bench_biguint_truncate_divide.mojo
index 3655b08..a0f20b9 100644
--- a/benches/biguint/bench_biguint_truncate_divide.mojo
+++ b/benches/biguint/bench_biguint_truncate_divide.mojo
@@ -30,7 +30,9 @@ fn open_log_file() raises -> PythonObject:
 
     # Generate a timestamp for the filename
     var timestamp = String(datetime.datetime.now().isoformat())
-    var log_filename = log_dir + "/benchmark_biguint_truncate_divide_" + timestamp + ".log"
+    var log_filename = (
+        log_dir + "/benchmark_biguint_truncate_divide_" + timestamp + ".log"
+    )
 
     print("Saving benchmark results to:", log_filename)
     return python.open(log_filename, "w")
diff --git a/benches/decimal/bench_truncate_divide.mojo b/benches/decimal/bench_truncate_divide.mojo
index c80fe9f..e8b2ec2 100644
--- a/benches/decimal/bench_truncate_divide.mojo
+++ b/benches/decimal/bench_truncate_divide.mojo
@@ -28,7 +28,9 @@ fn open_log_file() raises -> PythonObject:
 
     # Generate a timestamp for the filename
     var timestamp = String(datetime.datetime.now().isoformat())
-    var log_filename = log_dir + "/benchmark_truncate_divide_" + timestamp + ".log"
+    var log_filename = (
+        log_dir + "/benchmark_truncate_divide_" + timestamp + ".log"
+    )
 
     print("Saving benchmark results to:", log_filename)
     return python.open(log_filename, "w")
diff --git a/docs/changelog.md b/docs/changelog.md
index a755fe4..a8371de 100644
--- a/docs/changelog.md
+++ b/docs/changelog.md
@@ -2,9 +2,13 @@
 
 This is a list of RELEASED changes for the DeciMojo Package. For the unreleased changes, please refer to **[changelog_unreleased](https://zhuyuhao.com/decimojo/docs/changelog_unreleased.html)**.
 
+## 25/06/2025 (v0.4.0)
+
+DeciMojo v0.4.0 updates the codebase to Mojo v25.4. This release enables you to use DeciMojo with the latest Mojo features.
+
 ## 06/06/2025 (v0.3.1)
 
-DeciMojo v0.3.1 updates the codebase to Mojo 25.3 and replaces the `magic` package manager with `pixi`. This release enables you to use DeciMojo with the latest Mojo features and the new package manager.
+DeciMojo v0.3.1 updates the codebase to Mojo v25.3 and replaces the `magic` package manager with `pixi`. This release enables you to use DeciMojo with the latest Mojo features and the new package manager.
 
 ## 15/04/2025 (v0.3.0)
 
diff --git a/docs/readme_zht.md b/docs/readme_zht.md
index d0a3c0e..0051d53 100644
--- a/docs/readme_zht.md
+++ b/docs/readme_zht.md
@@ -20,7 +20,7 @@ DeciMojo 可在 [modular-community](https://repo.prefix.dev/modular-community) 
 
 從 `pixi` CLI，只需運行 ```pixi add decimojo```。這會獲取最新版本並使其立即可用於導入。
 
-對於帶有 `mojoproject.toml` 文件的項目，添加依賴 ```decimojo = ">=0.3.1"```。然後運行 `pixi install` 來下載並安裝包。
+對於帶有 `mojoproject.toml` 文件的項目，添加依賴 ```decimojo = "==0.4.0"```。然後運行 `pixi install` 來下載並安裝包。
 
 如需最新的開發版本，請克隆 [GitHub 倉庫](https://github.com/forfudan/decimojo) 並在本地構建包。
 
@@ -30,6 +30,7 @@ DeciMojo 可在 [modular-community](https://repo.prefix.dev/modular-community) 
 | v0.2.0     | >=25.2        | magic  |
 | v0.3.0     | >=25.2        | magic  |
 | v0.3.1     | >=25.2, <25.4 | pixi   |
+| v0.4.0     | ==25.4        | pixi   |
 
 ## 快速入門
 
@@ -217,7 +218,7 @@ DeciMojo 相較於 Python 的 `decimal` 模塊提供了卓越的性能，同時
     year         = {2025},
     title        = {DeciMojo: A fixed-point decimal arithmetic library in Mojo},
     url          = {https://github.com/forfudan/decimojo},
-    version      = {0.3.1},
+    version      = {0.4.0},
     note         = {Computer Software}
 }
 ```
diff --git a/pixi.toml b/pixi.toml
index ee6656b..e64af3c 100644
--- a/pixi.toml
+++ b/pixi.toml
@@ -7,10 +7,10 @@ license = "Apache-2.0"
 name = "decimojo"
 platforms = ["osx-arm64", "linux-64"]
 readme = "README.md"
-version = "0.3.1"
+version = "0.4.0"
 
 [dependencies]
-max = ">=25.2, <25.4"
+max = "==25.4"
 
 [tasks]
 # format the code
diff --git a/src/decimojo/bigdecimal/bigdecimal.mojo b/src/decimojo/bigdecimal/bigdecimal.mojo
index cf79f40..39c9f24 100644
--- a/src/decimojo/bigdecimal/bigdecimal.mojo
+++ b/src/decimojo/bigdecimal/bigdecimal.mojo
@@ -34,7 +34,9 @@ alias BDec = BigDecimal
 
 
 @value
-struct BigDecimal(Absable, Comparable, IntableRaising, Roundable, Writable):
+struct BigDecimal(
+    Absable, Comparable, IntableRaising, Roundable, Stringable, Writable
+):
     """Represents a arbitrary-precision decimal.
 
     Notes:
@@ -257,13 +259,13 @@ struct BigDecimal(Absable, Comparable, IntableRaising, Roundable, Writable):
             start = end - 9
             var word: UInt32 = 0
             for digit in coef[start:end]:
-                word = word * 10 + UInt32(digit[])
+                word = word * 10 + UInt32(digit)
             coefficient_words.append(word)
             end = start
         if end > 0:
             var word: UInt32 = 0
             for digit in coef[0:end]:
-                word = word * 10 + UInt32(digit[])
+                word = word * 10 + UInt32(digit)
             coefficient_words.append(word)
 
         coefficient = BigUInt(coefficient_words^)
@@ -871,7 +873,9 @@ struct BigDecimal(Absable, Comparable, IntableRaising, Roundable, Writable):
         var number_of_digits_to_remove = self.number_of_trailing_zeros()
 
         var number_of_words_to_remove = number_of_digits_to_remove // 9
-        var number_of_remaining_digits_to_remove = number_of_digits_to_remove % 9
+        var number_of_remaining_digits_to_remove = (
+            number_of_digits_to_remove % 9
+        )
 
         words = self.coefficient.words[number_of_words_to_remove:]
         var coefficient = BigUInt(words^)
diff --git a/src/decimojo/bigdecimal/exponential.mojo b/src/decimojo/bigdecimal/exponential.mojo
index 80434d2..3f1f0ed 100644
--- a/src/decimojo/bigdecimal/exponential.mojo
+++ b/src/decimojo/bigdecimal/exponential.mojo
@@ -551,15 +551,19 @@ fn sqrt(x: BigDecimal, precision: Int) raises -> BigDecimal:
     # TODO: This can be done even earlier in the process
     # TODO: Implement a method that remove trailing zeros
     if guess.coefficient.ith_digit(0) == 0:
-        var guess_coefficient_without_trailing_zeros = guess.coefficient.remove_trailing_digits_with_rounding(
-            guess.coefficient.number_of_trailing_zeros(),
-            rounding_mode=RoundingMode.ROUND_DOWN,
-            remove_extra_digit_due_to_rounding=False,
+        var guess_coefficient_without_trailing_zeros = (
+            guess.coefficient.remove_trailing_digits_with_rounding(
+                guess.coefficient.number_of_trailing_zeros(),
+                rounding_mode=RoundingMode.ROUND_DOWN,
+                remove_extra_digit_due_to_rounding=False,
+            )
         )
-        var x_coefficient_without_trailing_zeros = x.coefficient.remove_trailing_digits_with_rounding(
-            x.coefficient.number_of_trailing_zeros(),
-            rounding_mode=RoundingMode.ROUND_DOWN,
-            remove_extra_digit_due_to_rounding=False,
+        var x_coefficient_without_trailing_zeros = (
+            x.coefficient.remove_trailing_digits_with_rounding(
+                x.coefficient.number_of_trailing_zeros(),
+                rounding_mode=RoundingMode.ROUND_DOWN,
+                remove_extra_digit_due_to_rounding=False,
+            )
         )
         if (
             guess_coefficient_without_trailing_zeros
@@ -1036,7 +1040,7 @@ fn ln_series_expansion(
         k += BigUInt.ONE
 
         # Alternate sign: -1^(k+1) = -1 when k is even, 1 when k is odd
-        var sign = (k % BigUInt(2) == BigUInt.ZERO)
+        var sign = k % BigUInt(2) == BigUInt.ZERO
         var next_term = term.true_divide_inexact(
             BigDecimal(k, 0, False), working_precision
         )
diff --git a/src/decimojo/bigint/bigint.mojo b/src/decimojo/bigint/bigint.mojo
index 15b28af..65bbc23 100644
--- a/src/decimojo/bigint/bigint.mojo
+++ b/src/decimojo/bigint/bigint.mojo
@@ -37,7 +37,7 @@ alias BInt = BigInt
 
 
 @value
-struct BigInt(Absable, IntableRaising, Writable):
+struct BigInt(Absable, IntableRaising, Representable, Stringable, Writable):
     """Represents a base-10 arbitrary-precision signed integer.
 
     Notes:
diff --git a/src/decimojo/biguint/arithmetics.mojo b/src/decimojo/biguint/arithmetics.mojo
index e75925e..91c3b45 100644
--- a/src/decimojo/biguint/arithmetics.mojo
+++ b/src/decimojo/biguint/arithmetics.mojo
@@ -334,9 +334,11 @@ fn multiply(x1: BigUInt, x2: BigUInt) raises -> BigUInt:
             # Calculate the product of the current words
             # plus the carry from the previous multiplication
             # plus the value already at this position in the result
-            var product = UInt64(x1.words[i]) * UInt64(
-                x2.words[j]
-            ) + carry + UInt64(words[i + j])
+            var product = (
+                UInt64(x1.words[i]) * UInt64(x2.words[j])
+                + carry
+                + UInt64(words[i + j])
+            )
 
             # The lower 9 digits (base 10^9) go into the current word
             # The upper digits become the carry for the next position
@@ -881,9 +883,11 @@ fn floor_divide_inplace_by_double_words(
         x1.words.resize(len(x1.words) - 1, UInt32(0))
 
     for i in range(len(x1.words) - 1, -1, -2):
-        var dividend = carry * UInt128(1_000_000_000_000_000_000) + UInt128(
-            x1.words[i]
-        ) * UInt128(1_000_000_000) + UInt128(x1.words[i - 1])
+        var dividend = (
+            carry * UInt128(1_000_000_000_000_000_000)
+            + UInt128(x1.words[i]) * UInt128(1_000_000_000)
+            + UInt128(x1.words[i - 1])
+        )
         var quotient = dividend // x2_value
         x1.words[i] = UInt32(quotient // UInt128(1_000_000_000))
         x1.words[i - 1] = UInt32(quotient % UInt128(1_000_000_000))
diff --git a/src/decimojo/biguint/biguint.mojo b/src/decimojo/biguint/biguint.mojo
index 747365f..8a22a39 100644
--- a/src/decimojo/biguint/biguint.mojo
+++ b/src/decimojo/biguint/biguint.mojo
@@ -36,7 +36,7 @@ alias BUInt = BigUInt
 
 
 @value
-struct BigUInt(Absable, IntableRaising, Writable):
+struct BigUInt(Absable, IntableRaising, Stringable, Writable):
     """Represents a base-10 arbitrary-precision unsigned integer.
 
     Notes:
@@ -178,7 +178,7 @@ struct BigUInt(Absable, IntableRaising, Writable):
 
         # Check if the words are valid
         for word in words:
-            if word[] > UInt32(999_999_999):
+            if word > UInt32(999_999_999):
                 raise Error(
                     "Error in `BigUInt.from_list()`: Word value exceeds maximum"
                     " value of 999_999_999"
@@ -345,13 +345,13 @@ struct BigUInt(Absable, IntableRaising, Writable):
                 start = end - 9
                 var word: UInt32 = 0
                 for digit in coef[start:end]:
-                    word = word * 10 + UInt32(digit[])
+                    word = word * 10 + UInt32(digit)
                 result_words.append(word)
                 end = start
             if end > 0:
                 var word: UInt32 = 0
                 for digit in coef[0:end]:
-                    word = word * 10 + UInt32(digit[])
+                    word = word * 10 + UInt32(digit)
                 result_words.append(word)
 
             return Self(result_words^)
@@ -367,19 +367,21 @@ struct BigUInt(Absable, IntableRaising, Writable):
             for _ in range(remaining_trailing_zero_digits):
                 coef.append(UInt8(0))
 
-            var end: Int = number_of_digits + scale + remaining_trailing_zero_digits
+            var end: Int = (
+                number_of_digits + scale + remaining_trailing_zero_digits
+            )
             var start: Int
             while end >= 9:
                 start = end - 9
                 var word: UInt32 = 0
                 for digit in coef[start:end]:
-                    word = word * 10 + UInt32(digit[])
+                    word = word * 10 + UInt32(digit)
                 result_words.append(word)
                 end = start
             if end > 0:
                 var word: UInt32 = 0
                 for digit in coef[0:end]:
-                    word = word * 10 + UInt32(digit[])
+                    word = word * 10 + UInt32(digit)
                 result_words.append(word)
 
             return Self(result_words^)
diff --git a/src/decimojo/decimal/arithmetics.mojo b/src/decimojo/decimal/arithmetics.mojo
index c9f44e9..64456e3 100644
--- a/src/decimojo/decimal/arithmetics.mojo
+++ b/src/decimojo/decimal/arithmetics.mojo
@@ -221,8 +221,10 @@ fn add(x1: Decimal, x2: Decimal) raises -> Decimal:
             var ndigits_int_summation = ndigits_summation - x1_scale
             var final_scale = Decimal.MAX_NUM_DIGITS - ndigits_int_summation
 
-            var truncated_summation = decimojo.utility.round_to_keep_first_n_digits(
-                summation, Decimal.MAX_NUM_DIGITS
+            var truncated_summation = (
+                decimojo.utility.round_to_keep_first_n_digits(
+                    summation, Decimal.MAX_NUM_DIGITS
+                )
             )
             if truncated_summation > Decimal.MAX_AS_UINT128:
                 truncated_summation = (
@@ -610,15 +612,17 @@ fn multiply(x1: Decimal, x2: Decimal) raises -> Decimal:
     if combined_num_bits <= 128:
         var prod: UInt128 = x1_coef * x2_coef
         # Truncated first 29 digits
-        var truncated_prod_at_max_length = decimojo.utility.round_to_keep_first_n_digits(
-            prod, Decimal.MAX_NUM_DIGITS
+        var truncated_prod_at_max_length = (
+            decimojo.utility.round_to_keep_first_n_digits(
+                prod, Decimal.MAX_NUM_DIGITS
+            )
         )
 
         # Check outflow
         # The number of digits of the integral part
-        var num_digits_of_integral_part = decimojo.utility.number_of_digits(
-            prod
-        ) - combined_scale
+        var num_digits_of_integral_part = (
+            decimojo.utility.number_of_digits(prod) - combined_scale
+        )
         if (num_digits_of_integral_part >= Decimal.MAX_NUM_DIGITS) & (
             truncated_prod_at_max_length > Decimal.MAX_AS_UINT128
         ):
@@ -629,7 +633,9 @@ fn multiply(x1: Decimal, x2: Decimal) raises -> Decimal:
         # If the first 29 digits does not exceed the limit,
         # the final coefficient can be of 29 digits.
         # The final scale can be 29 - num_digits_of_integral_part.
-        var num_digits_of_decimal_part = Decimal.MAX_NUM_DIGITS - num_digits_of_integral_part
+        var num_digits_of_decimal_part = (
+            Decimal.MAX_NUM_DIGITS - num_digits_of_integral_part
+        )
         # If the first 29 digits exceed the limit,
         # we need to adjust the num_digits_of_decimal_part by -1
         # so that the final coefficient will be of 28 digits.
@@ -663,15 +669,17 @@ fn multiply(x1: Decimal, x2: Decimal) raises -> Decimal:
     var prod: UInt256 = UInt256(x1_coef) * UInt256(x2_coef)
 
     # Truncated first 29 digits
-    var truncated_prod_at_max_length = decimojo.utility.round_to_keep_first_n_digits(
-        prod, Decimal.MAX_NUM_DIGITS
+    var truncated_prod_at_max_length = (
+        decimojo.utility.round_to_keep_first_n_digits(
+            prod, Decimal.MAX_NUM_DIGITS
+        )
     )
 
     # Check outflow
     # The number of digits of the integral part
-    var num_digits_of_integral_part = decimojo.utility.number_of_digits(
-        prod
-    ) - combined_scale
+    var num_digits_of_integral_part = (
+        decimojo.utility.number_of_digits(prod) - combined_scale
+    )
 
     # Check for overflow of the integral part after rounding
     if (num_digits_of_integral_part >= Decimal.MAX_NUM_DIGITS) & (
@@ -684,7 +692,9 @@ fn multiply(x1: Decimal, x2: Decimal) raises -> Decimal:
     # If the first 29 digits does not exceed the limit,
     # the final coefficient can be of 29 digits.
     # The final scale can be 29 - num_digits_of_integral_part.
-    var num_digits_of_decimal_part = Decimal.MAX_NUM_DIGITS - num_digits_of_integral_part
+    var num_digits_of_decimal_part = (
+        Decimal.MAX_NUM_DIGITS - num_digits_of_integral_part
+    )
     # If the first 29 digits exceed the limit,
     # we need to adjust the num_digits_of_decimal_part by -1
     # so that the final coefficient will be of 28 digits.
@@ -979,11 +989,11 @@ fn divide(x1: Decimal, x2: Decimal) raises -> Decimal:
         var ndigits_quot = decimojo.utility.number_of_digits(quot)
         var ndigits_quot_int_part = ndigits_quot - scale_of_quot
 
-        print(
-            String(
-                "quot: {}, rem: {}, step_counter: {}, scale_of_quot: {}"
-            ).format(quot, rem, step_counter, scale_of_quot)
-        )
+        # print(
+        #     String(
+        #         "quot: {}, rem: {}, step_counter: {}, scale_of_quot: {}"
+        #     ).format(quot, rem, step_counter, scale_of_quot)
+        # )
 
         # TODO: 可以考慮先降 scale 再判斷是否超出最大值.
         # TODO: 爲降 scale 引入 round_to_remove_last_n_digits 函數
@@ -1014,8 +1024,8 @@ fn divide(x1: Decimal, x2: Decimal) raises -> Decimal:
                 scale_of_truncated_quot -= 1
 
             if scale_of_truncated_quot > Decimal.MAX_SCALE:
-                var num_digits_truncated_quot = decimojo.utility.number_of_digits(
-                    truncated_quot
+                var num_digits_truncated_quot = (
+                    decimojo.utility.number_of_digits(truncated_quot)
                 )
                 truncated_quot = decimojo.utility.round_to_keep_first_n_digits(
                     truncated_quot,
@@ -1120,8 +1130,8 @@ fn divide(x1: Decimal, x2: Decimal) raises -> Decimal:
                 scale_of_truncated_quot -= 1
 
             if scale_of_truncated_quot > Decimal.MAX_SCALE:
-                var num_digits_truncated_quot = decimojo.utility.number_of_digits(
-                    truncated_quot
+                var num_digits_truncated_quot = (
+                    decimojo.utility.number_of_digits(truncated_quot)
                 )
                 truncated_quot = decimojo.utility.round_to_keep_first_n_digits(
                     truncated_quot,
diff --git a/src/decimojo/decimal/decimal.mojo b/src/decimojo/decimal/decimal.mojo
index 7178e42..fcb93b2 100644
--- a/src/decimojo/decimal/decimal.mojo
+++ b/src/decimojo/decimal/decimal.mojo
@@ -43,7 +43,9 @@ struct Decimal(
     Comparable,
     Floatable,
     IntableRaising,
+    Representable,
     Roundable,
+    Stringable,
     Writable,
 ):
     """Represents a 128-bit fixed-point decimal number.
@@ -553,13 +555,13 @@ struct Decimal(
 
         for code in value_bytes:
             # If the char is " ", skip it
-            if code[] == 32:
+            if code == 32:
                 pass
             # If the char is "," or "_", skip it
-            elif code[] == 44 or code[] == 95:
+            elif code == 44 or code == 95:
                 unexpected_end_char = True
             # If the char is "-"
-            elif code[] == 45:
+            elif code == 45:
                 unexpected_end_char = True
                 if exponent_sign_read:
                     raise Error("Minus sign cannot appear twice in exponent.")
@@ -574,7 +576,7 @@ struct Decimal(
                     mantissa_sign = True
                     mantissa_sign_read = True
             # If the char is "+"
-            elif code[] == 43:
+            elif code == 43:
                 unexpected_end_char = True
                 if exponent_sign_read:
                     raise Error("Plus sign cannot appear twice in exponent.")
@@ -587,7 +589,7 @@ struct Decimal(
                 else:
                     mantissa_sign_read = True
             # If the char is "."
-            elif code[] == 46:
+            elif code == 46:
                 unexpected_end_char = False
                 if decimal_point_read:
                     raise Error("Decimal point can only appear once.")
@@ -595,7 +597,7 @@ struct Decimal(
                     decimal_point_read = True
                     mantissa_sign_read = True
             # If the char is "e" or "E"
-            elif code[] == 101 or code[] == 69:
+            elif code == 101 or code == 69:
                 unexpected_end_char = True
                 if exponent_notation_read:
                     raise Error("Exponential notation can only appear once.")
@@ -604,7 +606,7 @@ struct Decimal(
                 else:
                     exponent_notation_read = True
             # If the char is a digit 0
-            elif code[] == 48:
+            elif code == 48:
                 unexpected_end_char = False
 
                 # Exponent part
@@ -630,7 +632,7 @@ struct Decimal(
                         scale += 1
 
             # If the char is a digit 1 - 9
-            elif code[] >= 49 and code[] <= 57:
+            elif code >= 49 and code <= 57:
                 unexpected_end_char = False
 
                 # Exponent part
@@ -653,7 +655,7 @@ struct Decimal(
 
                     else:
                         # exponent_start = True
-                        raw_exponent = raw_exponent * 10 + UInt32(code[] - 48)
+                        raw_exponent = raw_exponent * 10 + UInt32(code - 48)
 
                 # Mantissa part
                 else:
@@ -665,7 +667,7 @@ struct Decimal(
                     mantissa_start = True
 
                     num_mantissa_digits += 1
-                    coef = coef * 10 + UInt128(code[] - 48)
+                    coef = coef * 10 + UInt128(code - 48)
 
                     if decimal_point_read:
                         scale += 1
@@ -673,7 +675,7 @@ struct Decimal(
             else:
                 raise Error(
                     String("Invalid character in decimal string: {}").format(
-                        chr(Int(code[]))
+                        chr(Int(code))
                     )
                 )
 
@@ -736,8 +738,8 @@ struct Decimal(
                 scale_of_truncated_coef -= 1
 
             if scale_of_truncated_coef > Decimal.MAX_SCALE:
-                var num_digits_truncated_coef = decimojo.utility.number_of_digits(
-                    truncated_coef
+                var num_digits_truncated_coef = (
+                    decimojo.utility.number_of_digits(truncated_coef)
                 )
                 truncated_coef = decimojo.utility.round_to_keep_first_n_digits(
                     truncated_coef,
@@ -1544,9 +1546,11 @@ struct Decimal(
             new_scale = Decimal.MAX_SCALE + 1
 
         # With UInt128, we can represent the coefficient as a single value
-        var coefficient = UInt128(self.high) << 64 | UInt128(
-            self.mid
-        ) << 32 | UInt128(self.low)
+        var coefficient = (
+            UInt128(self.high) << 64
+            | UInt128(self.mid) << 32
+            | UInt128(self.low)
+        )
 
         # TODO: Check if multiplication by 10^level would cause overflow
         # If yes, then raise an error
diff --git a/src/decimojo/decimal/exponential.mojo b/src/decimojo/decimal/exponential.mojo
index 967b7d6..1bf7086 100644
--- a/src/decimojo/decimal/exponential.mojo
+++ b/src/decimojo/decimal/exponential.mojo
@@ -204,23 +204,23 @@ fn root(x: Decimal, n: Int) raises -> Decimal:
     # For numbers with zero scale (true integers)
     if x_scale == 0:
         if n <= 8:  # 3<=n<=8
-            var float_root = pow(Float64(x_coef), 1 / Float64(n)) * Float64(
-                10
-            ) ** 8
+            var float_root = (
+                pow(Float64(x_coef), 1 / Float64(n)) * Float64(10) ** 8
+            )
             guess = Decimal.from_uint128(
                 UInt128(round(float_root)), scale=8, sign=False
             )
         elif n <= 16:
-            var float_root = pow(Float64(x_coef), 1 / Float64(n)) * Float64(
-                10
-            ) ** 16
+            var float_root = (
+                pow(Float64(x_coef), 1 / Float64(n)) * Float64(10) ** 16
+            )
             guess = Decimal.from_uint128(
                 UInt128(round(float_root)), scale=16, sign=False
             )
         else:
-            var float_root = pow(Float64(x_coef), 1 / Float64(n)) * Float64(
-                10
-            ) ** 26
+            var float_root = (
+                pow(Float64(x_coef), 1 / Float64(n)) * Float64(10) ** 26
+            )
             guess = Decimal.from_uint128(
                 UInt128(round(float_root)), scale=26, sign=False
             )
@@ -237,10 +237,9 @@ fn root(x: Decimal, n: Int) raises -> Decimal:
     else:
         var dividend = x_scale // n
         var remainder = x_scale % n
-        var float_root = (
-            Float64(x_coef) ** (Float64(1) / Float64(n))
-            / Float64(10) ** (Float64(remainder) / Float64(n) - 1)
-        )
+        var float_root = Float64(x_coef) ** (Float64(1) / Float64(n)) / Float64(
+            10
+        ) ** (Float64(remainder) / Float64(n) - 1)
         guess = Decimal.from_uint128(
             UInt128(float_root), scale=dividend + 1, sign=False
         )
@@ -278,7 +277,9 @@ fn root(x: Decimal, n: Int) raises -> Decimal:
         var num_digits_guess_coef = decimojo.utility.number_of_digits(
             guess_coef
         )
-        var num_digits_to_decrease = num_digits_guess_coef - num_digits_x_root_coef
+        var num_digits_to_decrease = (
+            num_digits_guess_coef - num_digits_x_root_coef
+        )
 
         # testing.assert_true(
         #     num_digits_to_decrease >= 0,
@@ -403,7 +404,9 @@ fn sqrt(x: Decimal) raises -> Decimal:
         var num_digits_guess_coef = decimojo.utility.number_of_digits(
             guess_coef
         )
-        var num_digits_to_decrease = num_digits_guess_coef - num_digits_x_sqrt_coef
+        var num_digits_to_decrease = (
+            num_digits_guess_coef - num_digits_x_sqrt_coef
+        )
 
         # testing.assert_true(
         #     num_digits_to_decrease >= 0,
diff --git a/src/decimojo/decimal/rounding.mojo b/src/decimojo/decimal/rounding.mojo
index b904e4d..e5dbe22 100644
--- a/src/decimojo/decimal/rounding.mojo
+++ b/src/decimojo/decimal/rounding.mojo
@@ -159,10 +159,6 @@ fn round(
         else:
             return Decimal.ZERO()
 
-    # Add a fallback raise even if it seems unreachable
-    testing.assert_true(False, "Unreachable code path reached")
-    return number
-
 
 fn quantize(
     value: Decimal,
diff --git a/src/decimojo/prelude.mojo b/src/decimojo/prelude.mojo
index fda9518..910dd26 100644
--- a/src/decimojo/prelude.mojo
+++ b/src/decimojo/prelude.mojo
@@ -16,7 +16,7 @@
 
 """
 Provides a list of things that can be imported at one time.
-The list contains the functions or types that are the most essential for a user. 
+The list contains the functions or types that are the most essential for a user.
 
 You can use the following code to import them:
 
@@ -26,8 +26,8 @@ from decimojo.prelude import *
 """
 
 import decimojo as dm
-from decimojo.decimal.decimal import Decimal
-from decimojo.bigdecimal.bigdecimal import BigDecimal
-from decimojo.biguint.biguint import BigUInt
-from decimojo.bigint.bigint import BigInt
-from decimojo.rounding_mode import RoundingMode
+from decimojo.decimal.decimal import Decimal, Dec
+from decimojo.bigdecimal.bigdecimal import BigDecimal, BDec
+from decimojo.biguint.biguint import BigUInt, BUInt
+from decimojo.bigint.bigint import BigInt, BInt
+from decimojo.rounding_mode import RoundingMode, RM
diff --git a/src/decimojo/rounding_mode.mojo b/src/decimojo/rounding_mode.mojo
index b972bd8..d9ff0e0 100644
--- a/src/decimojo/rounding_mode.mojo
+++ b/src/decimojo/rounding_mode.mojo
@@ -20,7 +20,7 @@
 alias RM = RoundingMode
 
 
-struct RoundingMode:
+struct RoundingMode(Stringable):
     """
     Represents different rounding modes for decimal operations.
 
diff --git a/src/decimojo/str.mojo b/src/decimojo/str.mojo
index 8064f26..ca5a68f 100644
--- a/src/decimojo/str.mojo
+++ b/src/decimojo/str.mojo
@@ -92,7 +92,7 @@ fn parse_numeric_string(
     var raw_exponent: Int = 0
 
     for code_ptr in value_bytes:
-        var code = code_ptr[]
+        ref code = code_ptr
         # If the char is " ", skip it
         if code == 32:
             pass
diff --git a/src/decimojo/tests.mojo b/src/decimojo/tests.mojo
index 19ffd43..c7f9aed 100644
--- a/src/decimojo/tests.mojo
+++ b/src/decimojo/tests.mojo
@@ -19,7 +19,7 @@ Implement structs and functions for tests.
 """
 
 
-struct TestCase:
+struct TestCase(Copyable, Movable):
     """Structure to hold test case data.
 
     Attributes:
diff --git a/src/tomlmojo/parser.mojo b/src/tomlmojo/parser.mojo
index b4edf61..8acded0 100644
--- a/src/tomlmojo/parser.mojo
+++ b/src/tomlmojo/parser.mojo
@@ -238,8 +238,8 @@ struct TOMLDocument:
             var value = self.root[key]
             if value.type == TOMLValueType.ARRAY:
                 for table_value in value.array_values:
-                    if table_value[].type == TOMLValueType.TABLE:
-                        result.append(table_value[].table_values)
+                    if table_value.type == TOMLValueType.TABLE:
+                        result.append(table_value.table_values)
 
         return result
 
diff --git a/tests/bigdecimal/test_bigdecimal_arithmetics.mojo b/tests/bigdecimal/test_bigdecimal_arithmetics.mojo
index 7768390..6061a56 100644
--- a/tests/bigdecimal/test_bigdecimal_arithmetics.mojo
+++ b/tests/bigdecimal/test_bigdecimal_arithmetics.mojo
@@ -106,7 +106,7 @@ fn test_subtract() raises:
     # Check what root keys are available
     print("Available root keys:")
     for key in toml.root.keys():
-        print("  - " + key[])
+        print("  - " + key)
 
     # Try to access the specific section
     try:
diff --git a/tests/decimal/test_sqrt.mojo b/tests/decimal/test_sqrt.mojo
index f793ce8..8b1a3b3 100644
--- a/tests/decimal/test_sqrt.mojo
+++ b/tests/decimal/test_sqrt.mojo
@@ -491,7 +491,9 @@ fn test_edge_cases() raises:
 
 fn test_precision() raises:
     print("Testing precision of square root calculations...")
-    var expected_sqrt2 = "1.414213562373095048801688724"  # First 10 decimal places of sqrt(2)
+    var expected_sqrt2 = (
+        "1.414213562373095048801688724"  # First 10 decimal places of sqrt(2)
+    )
 
     # Test precision for irrational numbers
     var two = Decimal(2)
@@ -749,125 +751,162 @@ fn test_sqrt_performance() raises:
         raise e
 
     # Test case 2
-    var num2 = Decimal("0.01")
-    var result2 = sqrt(num2)
-    var squared2 = result2 * result2
-    var diff2 = squared2 - num2
-    diff2 = -diff2 if diff2.is_negative() else diff2
-    var rel_diff2 = diff2 / num2
-    var diff_float2 = Float64(String(rel_diff2))
-    testing.assert_true(
-        diff_float2 < 0.00001,
-        "Square root calculation for "
-        + String(num2)
-        + " should be accurate within 0.001%",
-    )
+    try:
+        var num2 = Decimal("0.01")
+        var result2 = sqrt(num2)
+        var squared2 = result2 * result2
+        var diff2 = squared2 - num2
+        diff2 = -diff2 if diff2.is_negative() else diff2
+        var rel_diff2 = diff2 / num2
+        var diff_float2 = Float64(String(rel_diff2))
+        testing.assert_true(
+            diff_float2 < 0.00001,
+            "Square root calculation for "
+            + String(num2)
+            + " should be accurate within 0.001%",
+        )
+    except e:
+        print("ERROR in test_sqrt_performance case 2: small number 0.01")
+        raise e
 
     # Test case 3
-    var num3 = Decimal(1)
-    var result3 = sqrt(num3)
-    var squared3 = result3 * result3
-    var diff3 = squared3 - num3
-    diff3 = -diff3 if diff3.is_negative() else diff3
-    var rel_diff3 = diff3 / num3
-    var diff_float3 = Float64(String(rel_diff3))
-    testing.assert_true(
-        diff_float3 < 0.00001,
-        "Square root calculation for "
-        + String(num3)
-        + " should be accurate within 0.001%",
-    )
+    try:
+        var num3 = Decimal(1)
+        var result3 = sqrt(num3)
+        var squared3 = result3 * result3
+        var diff3 = squared3 - num3
+        diff3 = -diff3 if diff3.is_negative() else diff3
+        var rel_diff3 = diff3 / num3
+        var diff_float3 = Float64(String(rel_diff3))
+        testing.assert_true(
+            diff_float3 < 0.00001,
+            "Square root calculation for "
+            + String(num3)
+            + " should be accurate within 0.001%",
+        )
+    except e:
+        print("ERROR in test_sqrt_performance case 3: small number 1")
+        raise e
 
     # Test case 4
-    var num4 = Decimal(10)
-    var result4 = sqrt(num4)
-    var squared4 = result4 * result4
-    var diff4 = squared4 - num4
-    diff4 = -diff4 if diff4.is_negative() else diff4
-    var rel_diff4 = diff4 / num4
-    var diff_float4 = Float64(String(rel_diff4))
-    testing.assert_true(
-        diff_float4 < 0.00001,
-        "Square root calculation for "
-        + String(num4)
-        + " should be accurate within 0.001%",
-    )
+    try:
+        var num4 = Decimal(10)
+        var result4 = sqrt(num4)
+        var squared4 = result4 * result4
+        var diff4 = squared4 - num4
+        diff4 = -diff4 if diff4.is_negative() else diff4
+        var rel_diff4 = diff4 / num4
+        testing.assert_true(
+            rel_diff4 < Decimal(0.00001),
+            "Square root calculation for "
+            + String(num4)
+            + " should be accurate within 0.001%",
+        )
+    except e:
+        print("ERROR in test_sqrt_performance case 4: small number 10")
+        raise e
 
     # Test case 5
-    var num5 = Decimal(10000)
-    var result5 = sqrt(num5)
-    var squared5 = result5 * result5
-    var diff5 = squared5 - num5
-    diff5 = -diff5 if diff5.is_negative() else diff5
-    var rel_diff5 = diff5 / num5
-    var diff_float5 = Float64(String(rel_diff5))
-    testing.assert_true(
-        diff_float5 < 0.00001,
-        "Square root calculation for "
-        + String(num5)
-        + " should be accurate within 0.001%",
-    )
+    try:
+        var num5 = Decimal(10000)
+        var result5 = sqrt(num5)
+        var squared5 = result5 * result5
+        var diff5 = squared5 - num5
+        diff5 = -diff5 if diff5.is_negative() else diff5
+        var rel_diff5 = diff5 / num5
+        var diff_float5 = Float64(String(rel_diff5))
+        testing.assert_true(
+            diff_float5 < 0.00001,
+            "Square root calculation for "
+            + String(num5)
+            + " should be accurate within 0.001%",
+        )
+    except e:
+        print("ERROR in test_sqrt_performance case 5: small number 10000")
+        raise e
 
     # Test case 6
-    var num6 = Decimal("10000000000")
-    var result6 = sqrt(num6)
-    var squared6 = result6 * result6
-    var diff6 = squared6 - num6
-    diff6 = -diff6 if diff6.is_negative() else diff6
-    var rel_diff6 = diff6 / num6
-    var diff_float6 = Float64(String(rel_diff6))
-    testing.assert_true(
-        diff_float6 < 0.00001,
-        "Square root calculation for "
-        + String(num6)
-        + " should be accurate within 0.001%",
-    )
+    try:
+        var num6 = Decimal("10000000000")
+        var result6 = sqrt(num6)
+        var squared6 = result6 * result6
+        var diff6 = squared6 - num6
+        diff6 = -diff6 if diff6.is_negative() else diff6
+        var rel_diff6 = diff6 / num6
+        var diff_float6 = Float64(String(rel_diff6))
+        testing.assert_true(
+            diff_float6 < 0.00001,
+            "Square root calculation for "
+            + String(num6)
+            + " should be accurate within 0.001%",
+        )
+    except e:
+        print("ERROR in test_sqrt_performance case 6: small number 10000000000")
+        raise e
 
     # Test case 7
-    var num7 = Decimal("0.999999999")
-    var result7 = String(sqrt(num7))
-    var expected_result7 = String("0.99999999949999999987")
-    testing.assert_true(
-        result7.startswith(expected_result7), "sqrt(0.999999999)"
-    )
+    try:
+        var num7 = Decimal("0.999999999")
+        var result7 = String(sqrt(num7))
+        var expected_result7 = String("0.99999999949999999987")
+        testing.assert_true(
+            result7.startswith(expected_result7), "sqrt(0.999999999)"
+        )
+    except e:
+        print("ERROR in test_sqrt_performance case 7: sqrt(0.9999999999)")
+        raise e
 
     # Test case 8
-    var num8 = Decimal("1.000000001")
-    var result8 = String(sqrt(num8))
-    var expected_result8 = String("1.000000000499999999875")
-    testing.assert_true(
-        result8.startswith(expected_result8), "sqrt(1.000000001)"
-    )
+    try:
+        var num8 = Decimal("1.000000001")
+        var result8 = String(sqrt(num8))
+        var expected_result8 = String("1.000000000499999999875")
+        testing.assert_true(
+            result8.startswith(expected_result8), "sqrt(1.000000001)"
+        )
+    except e:
+        print("ERROR in test_sqrt_performance case 8: sqrt(1.000000001)")
+        raise e
 
     # Test case 9
-    var num9 = Decimal("3.999999999")
-    var result9 = sqrt(num9)
-    var squared9 = result9 * result9
-    var diff9 = squared9 - num9
-    diff9 = -diff9 if diff9.is_negative() else diff9
-    var rel_diff9 = diff9 / num9
-    var diff_float9 = Float64(String(rel_diff9))
-    testing.assert_true(
-        diff_float9 < 0.00001,
-        "Square root calculation for "
-        + String(num9)
-        + " should be accurate within 0.001%",
-    )
+    try:
+        var num9 = Decimal("3.999999999")
+        var result9 = sqrt(num9)
+        var squared9 = result9 * result9
+        var diff9 = squared9 - num9
+        diff9 = -diff9 if diff9.is_negative() else diff9
+        var rel_diff9 = diff9 / num9
+        var diff_float9 = Float64(String(rel_diff9))
+        testing.assert_true(
+            diff_float9 < 0.00001,
+            "Square root calculation for "
+            + String(num9)
+            + " should be accurate within 0.001%",
+        )
+    except e:
+        print("ERROR in test_sqrt_performance case 9: small number 3.999999999")
+        raise e
 
     # Test case 10
-    var num10 = Decimal("4.000000001")
-    var result10 = sqrt(num10)
-    var squared10 = result10 * result10
-    # Using manual absolute difference calculation
-    var diff10 = squared10 - num10
-    diff10 = -diff10 if diff10.is_negative() else diff10
-    var rel_diff10 = diff10 / num10
-    testing.assert_true(
-        rel_diff10 < Decimal("0.00001"),
-        "Square root calculation for "
-        + String(num10)
-        + " should be accurate within 0.001%",
-    )
+    try:
+        var num10 = Decimal("4.000000001")
+        var result10 = sqrt(num10)
+        var squared10 = result10 * result10
+        # Using manual absolute difference calculation
+        var diff10 = squared10 - num10
+        diff10 = -diff10 if diff10.is_negative() else diff10
+        var rel_diff10 = diff10 / num10
+        testing.assert_true(
+            rel_diff10 < Decimal("0.00001"),
+            "Square root calculation for "
+            + String(num10)
+            + " should be accurate within 0.001%",
+        )
+    except e:
+        print(
+            "ERROR in test_sqrt_performance case 10: small number 4.000000001"
+        )
+        raise e
 
     print("Performance and convergence tests passed!")