If a problem asks you to find the difference of two numbers, what operation would you perform?

If all of a roofing company`s 6 workers are required to staff 2 roofing crews, how many workers need to be added during the busy season so they can send 4 complete crews out on jobs?

A straight fence is to be constructed from posts 6 inches wide which are separated by chain link sections that are 8 feet long. If the fence must begin and end with a post, which of the following could NOT be the length of the fence?