exercices 59 transformer chaque expression en une suite d'addition puis la calculer URGENT

bonsoir

a = 7 + 5 - 11 + 4 - 7 = 16 - 18 = - 2

b = 13 - 5 - 14 - 17 + 13 = 26 - 36 = - 10

c = - 2.8 - 3.7 - 4.1 - 2.3 - 4.5 = - 17.4

d = - 8.1 - 3.6 - 9.7 + 8.2 + 2.4 = 10.6 - 21.4 = - 10.8

a=7+5-11+4-7=16-18=-2

b=13-5- 14-17+13=26-36=-10

c=-2.8-3.7-4.1-2.3-4.5=-17.4

d=-8.1-3.6-9.7+8.2+2.4=10.6-21.4=-10.8