Integers are the whole numbers and the negative numbers. (-3, -2, -1, 0, 1, 2, 3...) As you can imagine, it is not too difficult to make computers deal with negative numbers. Computer scientists simply add one more switch to a number which tells us if the number is positive or negative. You usually don't have to worry about this as a computer user, except you might need to specify in some way that you are working with an integer. (It makes a huge difference in some kinds of programs, and no difference at all in others. We will illustrate as you learn new kinds of applications.)