diff --git a/ui-ngx/src/app/modules/home/components/calculated-fields/components/dialog/calculated-field-dialog.component.html b/ui-ngx/src/app/modules/home/components/calculated-fields/components/dialog/calculated-field-dialog.component.html
index ad1154cc55..8e9baa6f90 100644
--- a/ui-ngx/src/app/modules/home/components/calculated-fields/components/dialog/calculated-field-dialog.component.html
+++ b/ui-ngx/src/app/modules/home/components/calculated-fields/components/dialog/calculated-field-dialog.component.html
@@ -79,6 +79,12 @@
           </div>
           <mat-form-field class="mt-3" appearance="outline" subscriptSizing="dynamic" [class.hidden]="fieldFormGroup.get('type').value !== CalculatedFieldType.SIMPLE">
             <input matInput formControlName="expressionSIMPLE" maxlength="255" [placeholder]="'(temperature - 32) / 1.8'" required>
+            <div  matSuffix
+                  class="pr-2"
+                  [tb-help-popup]="'math/math-methods_fn'"
+                  tb-help-popup-placement="left"
+                  [tb-help-popup-style]="{maxWidth: '970px'}">
+            </div>
             @if (configFormGroup.get('expressionSIMPLE').errors && configFormGroup.get('expressionSIMPLE').touched) {
               <mat-error>
                 @if (configFormGroup.get('expressionSIMPLE').hasError('required')) {
diff --git a/ui-ngx/src/app/modules/home/components/rule-node/action/math-function-config.component.html b/ui-ngx/src/app/modules/home/components/rule-node/action/math-function-config.component.html
index 6d8ac56fc1..3147162f06 100644
--- a/ui-ngx/src/app/modules/home/components/rule-node/action/math-function-config.component.html
+++ b/ui-ngx/src/app/modules/home/components/rule-node/action/math-function-config.component.html
@@ -32,6 +32,12 @@
     <legend class="group-title">{{'rule-node-config.custom-expression-field-input' | translate }} *</legend>
     <mat-form-field class="mat-block no-margin-top flex-1" subscriptSizing="dynamic">
       <input matInput formControlName="customFunction" required/>
+      <div  matSuffix
+            class="pr-2"
+            [tb-help-popup]="'math/math-methods_fn'"
+            tb-help-popup-placement="left"
+            [tb-help-popup-style]="{maxWidth: '970px'}">
+      </div>
       <mat-error *ngIf="mathFunctionConfigForm.get('customFunction').hasError('required')" translate>
         rule-node-config.custom-expression-field-input-required
       </mat-error>
diff --git a/ui-ngx/src/assets/help/en_US/math/math-methods_fn.md b/ui-ngx/src/assets/help/en_US/math/math-methods_fn.md
new file mode 100644
index 0000000000..9a5ddf3530
--- /dev/null
+++ b/ui-ngx/src/assets/help/en_US/math/math-methods_fn.md
@@ -0,0 +1,56 @@
+## Built-in operators
+The following operators can be used in expressions:
+
+| Operator | Description                   | Example         |
+|----------|-------------------------------|-----------------|
+| `+`      | Addition or unary plus        | `2 + 3` or `+3` |
+| `-`      | Subtraction or unary minus    | `5 - 2` or `-3` |
+| `*`      | Multiplication                | `4 * 2`         |
+| `/`      | Division                      | `10 / 2`        |
+| `^`      | Exponentiation                | `2 ^ 3`         |
+| `%`      | Modulo                        | `10 % 3`        |
+
+
+## Implicit multiplication
+Expressions supports implicit multiplication, allowing you to omit the multiplication operator in certain cases. For example, the expression `2cos(yx)` is interpreted as `2*cos(y*x)`. Similarly, `3x` is interpreted as `3*x`, and `xy` as `x*y`. This feature makes writing expressions more concise and natural.
+
+## Built-in constants
+Available constants for calculations:
+
+| Constant    | Description                 | Value             |
+|-------------|-----------------------------|-------------------|
+| `π` or `pi` | The mathematical constant π | 3.141592653589793 |
+| `e`         | Euler's number              | 2.718281828459045 |
+| `φ`         | The golden ratio            | 1.618033988749895 |
+
+## Built-in mathematical functions
+The following built-in mathematical functions can be used to perform various calculations:
+
+| Function      | Description                                                         | Example           |
+|---------------|---------------------------------------------------------------------|-------------------|
+| `abs(x)`      | Absolute value of `x`.                                              | `abs(-7) = 7`     |
+| `acos(x)`     | Arc cosine of `x`, result in radians. Requires `-1 ≤ x ≤ 1`.        | `acos(1) = 0`     |
+| `asin(x)`     | Arc sine of `x`, result in radians. Requires `-1 ≤ x ≤ 1`.          | `asin(0) = 0`     |
+| `atan(x)`     | Arc tangent of `x`, result in radians.                              | `atan(0) = 0`     |
+| `cbrt(x)`     | Cube root of `x`.                                                   | `cbrt(8) = 2`     |
+| `ceil(x)`     | Rounds `x` up to the nearest integer.                               | `ceil(3.1) = 4`   |
+| `cos(x)`      | Cosine of `x`, where `x` is in radians.                             | `cos(0) = 1`      |
+| `cosh(x)`     | Hyperbolic cosine of `x`.                                           | `cosh(0) = 1`     |
+| `cot(x)`      | Cotangent of `x` (1 / tan(`x`)), where `x` is in radians.           | `cot(0.7854) ≈ 1` |
+| `exp(x)`      | Computes `e^x`.                                                     | `exp(0) = 1`      |
+| `expm1(x)`    | Computes `e^x - 1` accurately for small `x`.                        | `expm1(0) = 0`    |
+| `floor(x)`    | Rounds `x` down to the nearest integer.                             | `floor(3.9) = 3`  |
+| `ln(x)`       | Natural logarithm (base *e*) of `x`. Requires `x > 0`.              | `ln(1) = 0`       |
+| `log(x)`      | Natural logarithm (base *e*) of `x`. Requires `x > 0`.              | `log(1) = 0`      |
+| `lg(x)`       | Natural logarithm (base 10) of `x`. Requires `x > 0`.               | `lg(10) = 1`      |
+| `log10(x)`    | Logarithm base 10 of `x`. Requires `x > 0`.                         | `log10(100) = 2`  |
+| `log2(x)`     | Logarithm base 2 of `x`. Requires `x > 0`.                          | `log2(8) = 3`     |
+| `logab(a, b)` | Logarithm of `b` with base `a`. Requires `a > 0`, `b > 0`, `a ≠ 1`. | `logab(2, 8) = 3` |
+| `log1p(x)`    | Computes `ln(1 + x)` accurately for small `x`. Requires `x > -1`.   | `log1p(0) = 0`    |
+| `pow(x, y)`   | Raises `x` to the power of `y` (`x^y`).                             | `pow(2, 3) = 8`   |
+| `signum(x)`   | Returns the sign of `x`: -1 if `x < 0`, 0 if `x = 0`, 1 if `x > 0`. | `signum(-5) = -1` |
+| `sin(x)`      | Sine of `x`, where `x` is in radians.                               | `sin(0) = 0`      |
+| `sinh(x)`     | Hyperbolic sine of `x`.                                             | `sinh(0) = 0`     |
+| `sqrt(x)`     | Square root of `x`. Requires `x ≥ 0`.                               | `sqrt(4) = 2`     |
+| `tan(x)`      | Tangent of `x`, where `x` is in radians.                            | `tan(0) = 0`      |
+| `tanh(x)`     | Hyperbolic tangent of `x`.                                          | `tanh(0) = 0`     |