In a program, you sometimes have to use a number multiple times. You can write in the numerical value every time you need it, but when you need to change the value, it is difficult to look for everywhere you used it in the program. Instead, you use a variable to hold the value and write the variable's name everywhere you would need that value. Whenever you change the variable's value, it changes for the entire program automatically. The "set variable" block can be used to create those variables:

Watch the video to learn more on how to use the "set variable" block.