 In this course, we'll primarily use F-strings, which we described in a previous video. Some of the videos you'll see in this course, and some programs you'll see in books, may have been written before F-strings. You might see a program like this that asks for a unit price and quantity, and gives a total price. Let's run the program and see it in action. If something costs 10.66 and I buy 11 of them, that's my total cost. This print statement looks a little like an F-string, and it does the same thing as an F-string using something called the format method. Let's take a closer look at the contents of the print function. We can mentally change this into an F-string by putting a letter F before the quote marks. And when we use format, the variables will all be at the end. We'll move them into the braces in the order they appear, giving us this. Then we get rid of the dot format and the parentheses, and there's our corresponding F-string. Now let's make that change to the program. I'll put an F before my string, and I'll use cut and paste to move my variables into the braces in order. Price goes into the second set of braces, and total into the third set of braces. Then I get rid of the dot format part, and I'm left with an F-string. When we run the program with the same price and number of units, we get the same output. So, when you see an old style format string, you can mentally translate it into the newer F-string. They're exactly the same, only different.