Réponse:
Salut!
A: 15/7 + -9/7 = 6/7
B: -3/8 - 15/8 = -18/8 = -9/4
C: -4/7 + 2/3 = -12/21 + 14/21 = 2/21
D: 4/9 - 7/54 = 24/54 - 7/54 = 17/54
E: 5/6 - 9/8 = 20/24 - 27/24 = -7/24
F: 5/12 + 3/4 = 10/24 + 18/24 = 28/24 = 7/6
G: 2 - 3/7 = 14/7 - 3/7 = 11/7
H: 4/3 + 1/6 - 7/12 = 16/12 + 2/12 - 7/12 = 11/12