To answer this question we need to find the factors of -120.
The total set (both negative and postive! ) are the following:
1, -120
2, -60
3, -40
4, -30
5, -24
6, -20
8, -15
10, -12
12, -10
15, -8
20, -6
24, -5
30, -4
40, -3
60, -2
120, -1
After looking over all of these factors, we can see that 10 · -12 is equal to not only -120, but when the multiplication sign is replace by addition, it is equal to -2!
