Modern computers have a large amount of main memory (also called RAM). This memory is used for many things. When you run a QBasic program, the statements of the program are stored in main memory. The data for the program also can be stored in main memory.

A variable in QBasic is a small amount of computer memory that has been given a name. You (the programmer) think of the name you want to use. The QBasic system will use a section of main memory for that name.

A variable is like a small box that holds a value. The value in the variable can change (that is why it is called a variable). Here is a program that uses a variable:

' Program that uses a variable
LET NUM = 23.5
PRINT "The variable contains", NUM

When this program runs, the value 23.5 is placed in the variable NUM. Then the following is written to the monitor:

The variable contains   23.5


What do you think the following program will write to the monitor?

' Program with a variable
LET NUM = 53
PRINT "The variable contains", NUM