First, you have to find two whole numbers whose product is 364. Then, you get each of their difference. If their difference, is 15, then that is the missing two whole numbers.
The product of 28 and 13 is 364. Their difference is 15. The question is, how much is their sum? If you are going to add 28 to 13, 41 is the sum. Therefore:
28x13=364
28-13=15
28+13=41
