It is: 63-4 = 59
63 minus 21 is 42.
It is: 63/91 = 9/13
The factors of 63 are: 1, 3, 7, 9, 21, 63 The factors of 91 are: 1, 7, 13, 91
The common factors of 63 and 91 are 1 and 7.
91 - 38 = 53
91 - 16 = 75
63 - 10 = 53
100 - 63 = 37
63 - 37 = 26
45 - 63 = -18
-16 - 63 = -79