The greatest common factor is the biggest factor that divides two different numbers. For example, the greatest common factor of 6 and 8 is 2. The least common multiple is the smallest number that two numbers share as a multiple. For example, 12 is a the lowest common multiple of 3 and 4.
3 is the cost of one pair of shoes and 4 is how many shoes were rented. you multiple the 3 times 4 and get 12 and to get the amount of one game you have to subtract the total amount. the equation I came up with might not be what your teacher wants but thats a start. hope it helped!