An example of this would be wanting to increase the price of an item of a Food item. In the Food class, we can define a method with a return of type decimal and return a 30% increase in the price of the Food item.
Then in the MainWindow we can call that method on the MonkeyTail object and assign the result to a newPrice variable.
We can then use that variable to assign a new Price value to the MonkeyTail.
Once we execute that line of code, the MonkeyTail will have the new price.