**Functions** are blocks of code that perform a specific task and can be called multiple times within a program. By using functions, we can avoid repeating the same code, which makes our program cleaner and more organized. functions are declared using **fun** keyword in kotlin

Let’s create a simple example that calculates the area of a rectangle

```
fun calculateRectangleArea(length: Double, width: Double): Double {
val area = length * width
return area
}
```

Now, you can use this function to calculate the area of any rectangle by passing the appropriate values for length and width. For example:

```
fun main() {
// Calculate the area of a rectangle with length 5 and width 3
val area1 = calculateRectangleArea(5.0, 3.0)
println("Area of the rectangle: $area1")
// Calculate the area of another rectangle with length 7 and width 4.5
val area2 = calculateRectangleArea(7.0, 4.5)
println("Area of the rectangle: $area2")
}
```

```
Output:
Area of the rectangle: 15.0
Area of the rectangle: 31.5
```