50 + 6 = 56
7 + 1 = 8
10 x 8 = 80
56 x 80 = 4480
4480 - 1 = 4479

50 - 1 = 49
49 + 7 = 56
10 x 6 = 60
1 + 56 = 57
60 + 57 = 117