Bonjour !
-4 + (-7) = - 4 - 7 = - (4+7) = -11
-7 - (+2) = - 7 - 2 = - (7+2) = -9
-7 - 11 = - (7+11) = -18
-10 + 6 = - (10-6) = -4
-9 + (+12) = -9 + 12 = 12 - 9 = 3
(+8) - (-10) = +8 + 10 = 18
9 - 13 = - (13-9) = -4
-28 + 28 = 28 - 28 = 0
N'hésite pas si tu as des questions :)
