If the number is 500
that means that 1% is 5 because 5 x 100 = 500. That means
that 4% is 5 + 5 + 5 + 5 which is 20. That means that 500 +- 4% is equal
to 500 +- 20, meaning that the range is from 480 to 520,
which is 40 whole numbers
Four percent of 500 is 20. Thus, we have the range of values (500-20, 500+20), or (480, 520).
