Functions act as placeholders for the data they output. Basically, you can assign the output of a function to a variable, just like any normal data.The core concept of this lesson is to learn how to call a function and assign the return value to a variable. FreeCodeCamp offers a curriculum and in this video we cover their lesson called Assignment with a Returned Value. Return values are being specified for error conditions for all functions. Make sure you use the specified return value as well as print out the error message. We can take the return value of a function and assign it to a variable. Assume we have pre-defined a function sum which adds two numbers together. You are expected to complete this assignment individually. When we have variables and we're assigning it to a value what's the saying is that whenever we have a whatever is on the right of the equal sign.