diff --git a/public/dimensional_analysis.py b/public/dimensional_analysis.py
index ac7c94bf..e1c7ee28 100644
--- a/public/dimensional_analysis.py
+++ b/public/dimensional_analysis.py
@@ -940,6 +940,34 @@ def custom_norm(expression: Matrix):
 def custom_dot(exp1: Matrix, exp2: Matrix):
     return exp1.dot(exp2)
 
+def custom_derivative(expr: Expr, dummy_diff_var: Symbol, diff_var: Expr, order: int | None = None):
+    if order is not None:
+        return Derivative(expr, dummy_diff_var, order, evaluate=True).subs({dummy_diff_var: diff_var})
+    else:
+        return Derivative(expr, dummy_diff_var, evaluate=True).subs({dummy_diff_var: diff_var})
+    
+def custom_derivative_dims(expr: Expr, dummy_diff_var: Symbol, diff_var: Expr, order: int | None = None):
+    if order is None:
+        order = 1
+    return expr.subs({dummy_diff_var: diff_var}) / diff_var**order # type: ignore
+
+def custom_integral(expr: Expr, dummy_integral_var: Symbol, integral_var: Expr, 
+                    lower_limit: Expr | None = None, upper_limit: Expr | None = None, 
+                    lower_limit_dims: Expr | None = None, upper_limit_dims: Expr | None = None):
+    if lower_limit is not None and upper_limit is not None:
+        return Integral(expr, (dummy_integral_var, lower_limit, upper_limit)).subs({dummy_integral_var: integral_var})
+    else:
+        return Integral(expr, dummy_integral_var).subs({dummy_integral_var: integral_var})
+    
+def custom_integral_dims(expr: Expr, dummy_integral_var: Symbol, integral_var: Expr, 
+                    lower_limit: Expr | None = None, upper_limit: Expr | None = None, 
+                    lower_limit_dims: Expr | None = None, upper_limit_dims: Expr | None = None):
+    if lower_limit is not None and upper_limit is not None:
+        ensure_dims_all_compatible(lower_limit_dims, upper_limit_dims)
+        return expr.subs({dummy_integral_var: lower_limit_dims}) * lower_limit_dims # type: ignore
+    else:
+        return expr.subs({dummy_integral_var: integral_var}) * integral_var # type: ignore
+
 placeholder_map: dict[Function, PlaceholderFunction] = {
     cast(Function, Function('_StrictLessThan')) : {"dim_func": ensure_dims_all_compatible, "sympy_func": StrictLessThan},
     cast(Function, Function('_LessThan')) : {"dim_func": ensure_dims_all_compatible, "sympy_func": LessThan},
@@ -971,6 +999,8 @@ def custom_dot(exp1: Matrix, exp2: Matrix):
     cast(Function, Function('_ceil')) : {"dim_func": ensure_unitless_in, "sympy_func": ceiling},
     cast(Function, Function('_floor')) : {"dim_func": ensure_unitless_in, "sympy_func": floor},
     cast(Function, Function('_round')) : {"dim_func": ensure_unitless_in, "sympy_func": custom_round},
+    cast(Function, Function('_Derivative')) : {"dim_func": custom_derivative_dims, "sympy_func": custom_derivative},
+    cast(Function, Function('_Integral')) : {"dim_func": custom_integral_dims, "sympy_func": custom_integral}
 }
 
 placeholder_set = set(placeholder_map.keys())
@@ -1686,7 +1716,7 @@ def combine_plot_results(results: list[Result | FiniteImagResult | PlotResult |
 
 
 def subs_wrapper(expression: Expr, subs: dict[str, str] | dict[str, Expr | float] | dict[Symbol, Symbol]) -> Expr:
-    if len(expression.atoms(Integral, Derivative)) > 0:
+    if len(expression.atoms(Subs)) > 0:
         # must use slower subs when substituting parameters that may be in a integral or derivative
         # subs automatically delays substitution by wrapping integral or derivative in a subs function
         return cast(Expr, expression.subs(subs))
diff --git a/src/App.svelte b/src/App.svelte
index 56e1b82c..326f9735 100644
--- a/src/App.svelte
+++ b/src/App.svelte
@@ -90,7 +90,7 @@
 
   const apiUrl = window.location.origin;
 
-  const currentVersion = 20240321;
+  const currentVersion = 20240324;
   const tutorialHash = "fFjTsnFoSQMLwcvteVoNtL";
 
   const termsVersion = 20240110;
diff --git a/src/Updates.svelte b/src/Updates.svelte
index fc621451..5ffae423 100644
--- a/src/Updates.svelte
+++ b/src/Updates.svelte
@@ -16,6 +16,20 @@
   }
 </style>
 
+<em>March 24, 2024</em>
+<h4>Differentiation and Integration Bug Fixes</h4>
+<p>
+   Two bugs that occur in certain situations when performing substitutions
+   with 
+   <a href="https://github.com/mgreminger/EngineeringPaper.xyz/issues/156" target="_blank">derivatives</a>
+   and
+   <a href="https://github.com/mgreminger/EngineeringPaper.xyz/issues/244" target="_blank">integrals</a>
+   have been fixed. This fix also has the benefit of speeding up calculations for sheets that
+   make use of derivatives or integrals.
+</p>
+
+<br>
+
 <em>March 21, 2024</em>
 <h4>Custom Right Click Context Menu Added</h4>
 <p>
diff --git a/src/parser/LatexToSympy.ts b/src/parser/LatexToSympy.ts
index efd06dcb..b4d3a8da 100644
--- a/src/parser/LatexToSympy.ts
+++ b/src/parser/LatexToSympy.ts
@@ -1235,7 +1235,8 @@ export class LatexToSympy extends LatexParserVisitor<string | Statement | UnitBl
         this.insertTokenCommand('mathrm', child.id(0).children[0] as TerminalNode);
       }
       const variableOfIntegration = this.mapVariableNames(this.visitId(child.id(1)));
-      return `Integral(${this.visit(child.expr())}, ${variableOfIntegration})`;
+      this.params.push(variableOfIntegration);
+      return `_Integral(Subs(${this.visit(child.expr())}, ${variableOfIntegration}, ${variableOfIntegration}__dummy_var), ${variableOfIntegration}__dummy_var, ${variableOfIntegration})`;
     }
   }
 
@@ -1251,6 +1252,7 @@ export class LatexToSympy extends LatexParserVisitor<string | Statement | UnitBl
         this.insertTokenCommand('mathrm', child.id(0).children[0] as TerminalNode);
       }
       const variableOfIntegration = this.mapVariableNames(this.visitId(child.id(1)));
+      this.params.push(variableOfIntegration);
 
       let lowerLimit: string;
       let upperLimit: string;
@@ -1275,7 +1277,7 @@ export class LatexToSympy extends LatexParserVisitor<string | Statement | UnitBl
         upperLimit = child.CARET_SINGLE_CHAR_NUMBER().toString()[1];
       }
 
-      return `Integral(${integrand}, (${variableOfIntegration}, ${lowerLimit}, ${upperLimit}))`;
+      return `_Integral(Subs(${integrand}, ${variableOfIntegration}, ${variableOfIntegration}__dummy_var), ${variableOfIntegration}__dummy_var, ${variableOfIntegration}, Subs(${lowerLimit}, ${variableOfIntegration}, ${variableOfIntegration}__dummy_var), Subs(${upperLimit}, ${variableOfIntegration}, ${variableOfIntegration}__dummy_var), ${lowerLimit}, ${upperLimit})`;
     }
   }
 
@@ -1295,7 +1297,8 @@ export class LatexToSympy extends LatexParserVisitor<string | Statement | UnitBl
         this.insertTokenCommand('mathrm', child.id(1).children[0] as TerminalNode);
       }
       const variableOfDifferentiation = this.mapVariableNames(this.visitId(child.id(2)));
-      return `Derivative(${this.visit(child.expr())}, ${variableOfDifferentiation}, evaluate=False)`;
+      this.params.push(variableOfDifferentiation);
+      return `_Derivative(Subs(${this.visit(child.expr())}, ${variableOfDifferentiation}, ${variableOfDifferentiation}__dummy_var), ${variableOfDifferentiation}__dummy_var, ${variableOfDifferentiation})`;
     }
   }
 
@@ -1339,7 +1342,8 @@ export class LatexToSympy extends LatexParserVisitor<string | Statement | UnitBl
         this.insertTokenCommand('mathrm', child.id(1).children[0] as TerminalNode);
       }
       const variableOfDifferentiation = this.mapVariableNames(this.visitId(child.id(2)));
-      return `Derivative(${this.visit(child.expr())}, ${variableOfDifferentiation}, ${exp1}, evaluate=False)`;
+      this.params.push(variableOfDifferentiation);
+      return `_Derivative(Subs(${this.visit(child.expr())}, ${variableOfDifferentiation}, ${variableOfDifferentiation}__dummy_var), ${variableOfDifferentiation}__dummy_var, ${variableOfDifferentiation}, ${exp1})`;
     }
   }
 
diff --git a/tests/test_calc.spec.mjs b/tests/test_calc.spec.mjs
index 95740452..a765f7c4 100644
--- a/tests/test_calc.spec.mjs
+++ b/tests/test_calc.spec.mjs
@@ -179,3 +179,83 @@ test('Test substitution of differential variable', async () => {
   expect(content).toBe('');
 });
 
+
+test('Test derivative substitution bug #156', async () => {
+
+  await page.setLatex(0, String.raw`y=20\cdot x`);
+  
+  await page.keyboard.press('Shift+Enter');
+  await page.setLatex(1, String.raw`\frac{\mathrm{d}}{\mathrm{d}\left(x\right)}\left(x\cdot y\right)=`);
+
+  await page.waitForSelector('.status-footer', {state: 'detached'});
+
+  let content = await page.textContent('#result-value-1');
+  expect(content).toBe('40 x');
+
+});
+
+
+test('Test integral substitution bug #244', async () => {
+
+  await page.setLatex(0, String.raw`c=a\left(b=1\right)`);
+  
+  await page.keyboard.press('Shift+Enter');
+  await page.setLatex(1, String.raw`\int_0^1\left(c\cdot x\right)\mathrm{d}\left(x\right)=`);
+
+  await page.click('#add-piecewise-cell');
+
+  await page.locator('#piecewise-parameter-2 math-field.editable').type('a');
+  await page.locator('#piecewise-expression-2-0 math-field.editable').type('1');
+  await page.locator('#piecewise-expression-2-1 math-field.editable').type('-1');
+  await page.locator('#piecewise-condition-2-0 math-field.editable').type('b>=0');
+
+  await page.waitForSelector('.status-footer', {state: 'detached'});
+
+  let content = await page.textContent('#result-value-1');
+  expect(parseLatexFloat(content)).toBeCloseTo(0.5, precision);
+
+});
+
+
+test('Test definite integral with numerical limits that have units', async () => {
+
+  await page.setLatex(0, String.raw`\int_{0\left\lbrack m\right\rbrack}^{1\left\lbrack m\right\rbrack}\left(x\right)\mathrm{d}\left(x\right)=`);
+
+  await page.keyboard.press('Shift+Enter');
+  await page.setLatex(1, String.raw`\int_0^{1\left\lbrack m\right\rbrack}\left(x\right)\mathrm{d}\left(x\right)=`);
+
+  await page.waitForSelector('.status-footer', {state: 'detached'});
+
+  let content = await page.textContent('#result-value-0');
+  expect(parseLatexFloat(content)).toBeCloseTo(0.5, precision);
+  content = await page.textContent('#result-units-0');
+  expect(content).toBe('m^2');
+
+  await expect(page.locator("#cell-1 >> text=Dimension Error")).toBeAttached();
+
+});
+
+
+test('Test units for nth order derivatives', async () => {
+
+  await page.setLatex(0, String.raw`\frac{\mathrm{d}^2}{\mathrm{d}\left(y\right)^2}\left(1\right)=`);
+
+  await page.keyboard.press('Shift+Enter');
+  await page.setLatex(1, String.raw`\frac{\mathrm{d}^2}{\mathrm{d}\left(y\right)^2}\left(y^3\right)=`);
+
+  await page.keyboard.press('Shift+Enter');
+  await page.setLatex(2, String.raw`y=1\left\lbrack m\right\rbrack`);
+
+  await page.waitForSelector('.status-footer', {state: 'detached'});
+
+  let content = await page.textContent('#result-value-0');
+  expect(parseLatexFloat(content)).toBeCloseTo(0, precision);
+  content = await page.textContent('#result-units-0');
+  expect(content).toBe('m^-2');
+
+  content = await page.textContent('#result-value-1');
+  expect(parseLatexFloat(content)).toBeCloseTo(6, precision);
+  content = await page.textContent('#result-units-1');
+  expect(content).toBe('m');
+
+});
\ No newline at end of file