Sagot :

Bonjour,

exercice 26

1)

4*1 =4

4*2=8

4*3 = 12

6*1=6

6*2=12

2)

a= 3/12 +2/12 =  5/12

b= 9/12 + 10/12 = 19/12

c= 21/12 -4/12 = 17/12

d= -33/12 - 14/12 = -47/12

e= 3/12 -2/12 = 1:12

f= 3/12 +10/12 = 13/12

exercice 28

a)

18/63 + 7/63 = 25/63

b)

40/15 - 9/15 =31/15

c)

45/6 - 35/6 = 10/6 = 5/3