Look for the number that is marked farthest to the right on the line. The farther to the right that you move on a number line, the greater the value of the number will be.
Look for the highest positive number in a set of positive numbers or a set of negative and positive numbers. For instance, consider following numbers graphed on a number line: -6, -4, 2, 7. The greatest positive number in this group is 7.
Remove the negative signs mentally and look for the lowest number among a group of negative numbers to find the greatest value. For example, consider the following values: -10, -8, -5, -1. If you take away the negative signs, 1 would be the lowest number. Therefore, -1 is the greatest number in this set.