 Therefore, 12 is the greatest common divisor of 24 and 60.A 24-by-60 rectangular area can be divided into a grid of 12-by-12 squares, with two squares along one edge (24/12 = 2) and five squares along the other (60/12 = 5).The GCD of two numbers "a" and "b" is the product of the prime factors shared by the two numbers, where a same prime factor can be used multiple times, but only as long as the product of these factors divides both "a" and "b".