In math, the range in a set of numbers is simply the difference between the largest and smallest number. To find the range take the larger number and subtract the smaller from it. For example, look at this set of numbers. 44,66,87,34,65,67,89,98 and 39. The largest number is 98, the smalles 34. When we subtract the two we find the range of the set of numbers is 64. Easy!