100 x 9 = 900
20 x 9 = 180
8 x 9 = 72
900 + 180 + 72 = 1152
86 x 12 = 1032
80 x 12 = 960
6 x 12 = 72
960 + 72 = 1032
43 x 15 = 645
40 x 15 = 600
3 x 15 = 45
600 + 45 = 645
123 x 45 = 5535
100 x 45 = 4500
20 x 45 =900
3 x 45 = 135
4500 + 900 + 135 = 5535