how is the coordinate system used for computers?

1. Calculate the number of action figures sold on Monday:
8 comic books for every 3 action figuress
32 comic books = ? action figures
8 x 4 = 32
so 3 x 4 = 12 action figures sold on Monday

2. Find the difference between the number of action figures sold on Monday and Tuesday
They're asking for the difference, so you subtract
18 - 12 = 6
Hence, the difference in the number of books on Monday and Tuesday is 6