题目内容：

the difference between 15 and the product of 5 and y
5y-15 和 15-5y.哪个是对的,为什么?（一定要为什么!

优质解答

15- 5y is the right one.the difference between A and b means A-b
here the A means 15 and the B mean the product of 5 and y