Welcome, learners! Today, we're diving into function return values in Kotlin programming. Function return values, often simply referred to as "returns," are results given back by a function after performing its assigned task. This concept is signified in Kotlin with the keyword return.

Here's a simple example of a function greet() that returns a String:

Now, let's get more practical. Suppose we want our function to perform a calculation—an addition operation in a calculator program, for instance. Here's how we can write a function that adds two numbers and returns the sum:

Let's see this function in action within Kotlin's main function:

Returns are not always simple numbers. A function can return any type of data from the range Kotlin supports, including Int, String, , , , and . Let's explore this further using the calculation of a circle's area as an example, which is πr².