Réponse :
Explications étape par étape
Bonjour
4+(-7) = 4-7 = 63
-8 +(-9) = -8 -9 = -17
9+(-12) = 9-12 = -3
6+(-8) = -2
21+(-10) = 21-10 = 11
-5 +(+1) = -5+1 = -4
-7 +( -9) = -7 -9 = -16
