Réponse :
bonjour,
A = +10 - (-12) = 10 + 12 = 22
B =(-21) - (+13) = -21 - 13 = -34
C = (-9) - (+14) = -9 - 14 = -23
D = (+12.4) - (-9.7) = 12.4 + 9.7 = 22.1
E = (-65) - ( -78) = -65 + 78 = 13
F = (-1.1) - (+0.2) = -1.1 - 0.2 = -1.3
G =(+ 3) - ( +3.5) = 3 - 3.5 = -0.5
H = (-0.1) - (-0.1) = -0.1 + 0.1 = 0
voila:)