Problem: by how much is 21 greater than product of 3 1/5 and 5 3/4.
I think we will first get the product before divividing by 21
You are correct about getting the product first.
3 1/5 * 5 3/4 = 16/5 * 23/4 = (16 * 23) / (5 * 4)
(16 * 23) / (5 * 4) = 368/20 = 18.4
However, you DO NOT divide by 21. The problem asks how much
is 21 greater than the product. That means you SUBTRACT the
product FROM 21.
21 - 18.4 = 2.6
Answer: 21 is 2.6 greater than the product of 3 1/5 and 5 3/4.