Réponse:
exercice 7:
a) 13x2/5= 5,2
b) 6x7/4= 10,5
c) 3,2x2,4/6= 1,28
d) 36x3,2/7,2= 16
exercice 8
12x40/15
x=32
5,6x40/32
y=7
5,6x3,6/7
z= 2,88
