Réponse :
Ex 2
a) 1/9+2/3
=1/9+6/9
=7/9
b)5/18-1/9
=5/18-2/18
=3/18=1/6
c)2/3-1/9+5/18
=12/18-2/18+5/18
=15/18=5/6
d)2/3-5/18 +2/3-1/9
=12/18-5/18+12/18-2/18
=17/18
Ex 3
2/15+1/9
=6/45+5/45
=11/45
donc 45/45 -11/45=34/45
donc Rania et Rachelle prennent
(34/45):2=34/45*1/2=34/90 =17/45
