A slow way to calculate the distance between numbers on a number line is to count every number between them. A simpler, faster way is to find the distance through subtraction and absolute values. An absolute value is the positive representation for a number and is symbolized as |a|. For example, the absolute values of 3 and -3, or |3| and |-3|, are both 3. This method of number line distance works for numbers close together and far apart.
Select two numbers on the number line. For this example, the numbers are -9 and 5.
Subtract one number on the number line from the other number. For this example, -9 subtracted from 5 is 14. If subtracting 5 from -9, the answer would be -14.
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Obtain the absolute value of the number line difference. For this example, the absolute value for either 14 or -14 -- that is, |14| or |-14| -- is 14. The distance between the two numbers is 14.