7 - 9 = -2
If you have 7 things and try to take away 9 you can't because there aren't enough. Hence the things you don't have are represented by -2.
-9 - (-7) = -2
9 - 7 = 2
-7. Minus seven.
It is 9*6 minus 7 = 47
7/9 minus 2/9 is 5/9
9 minus 7 = 2
-16 minus -9 is -7
5
-9 minus -2 is -7
9/10 minus 7/8 is 1/40
7/9 minus 3/4 is 1/36
8/9 minus 7/12 is 11/36
1 -------- 9-7 -------- 9
10 minus 9/8 is 8 7/8