svp svp aider moi jarrive pas

a) 18*2/3
= 18*3/1*3 * 2/3
= 54/3 * 2/3
= 108/9 = 12/1 = 12

b) 28/7 * 5
= 28*5/7
= 20

c) 3.5 * 9/5
3.5*10 / 1*10 * 9*2 / 5*2
= 35/10 * 18/10
= 630/100 = 63/10

d) 8/48 * 6
= 8*6/48
= 48/48 = 1

e) 120*5/6
= 120*5/6
= 100

f) 7/2 * 2.8
= 7*5 / 2*5 * 2.8*10/10*1
= 35/10 * 28/10
= 980/100 = 98/10

bon courage :)