Explications étape par étape :
B = -3/8 - 5/12
= -18/48 - 20/48
= -38/48
C = -5/12 + 7/18
= -15/36 + 14/36
= -1/36
D = -7/6 - 11/12 + 5/9
= -42/36 - 33/36 + 20/36
= -75/36 + 20/36
= -55/36
E = (5/32 + 3/16) - (7/8 - 1/12)
= (5/32 + 6/32) - (28/32 - 3/32)
= 11/32 - 25/32
= -14/32
