A = 9x3 / 8x3 - 5x4 / 6x4
A = 27 / 24 - 20 / 24
A = 7
B = 3 x 5 / 7 x 4
B = 15 / 28
C = 5 % 8 / 4 % 7
C = 5 x 7 / 4 x 8
C = 35 / 32
D = 5 x 7 / 3 x 4 + 7 / 6
D = 35 / 12 + 7x2 / 6x2
D = 35 / 12 + 14 / 12
D = 49 / 12