To find the difference between two numbers, we subtract them. Usually, we subtract them in the order they are named. For example, “the difference of +8 and -6” means 8 −(-6). We can find the value of 8−(-6) by thinking -6+?=8. Representing this on a number line, we can see that the second arrow must be 14 units long, pointing to the right.
The difference of two numbers tells us how far apart they are on the number line and in which direction. The difference of +8 and -6 is 14 because these numbers are 14 units apart, and 8 is to the right of -6.
If we subtract the same numbers in the opposite order, we get the opposite number. For example, “the difference of -6 and +8” means -6−8. This difference is -14 because these numbers are 14 units apart, and -6 is to the left of +8.
In general, the distance between two numbers a and b on the number line is ∣a−b∣. Note that the distance between two numbers is always positive, no matter the order. But the difference can be positive or negative, depending on the order.