bonsoir voici la réponse détaillée
EXERCICE 3 :
a) (1/2)+(1/3)+(1/4)+(1/5)+(1/6)= 145/100=29/20
b) (1/2)-(1/3)+(1/4)-(1/5)+(1/6)= 383/1000
c) (7/11)-(9/15)+(17/9)-(5/6)+(7/5)= 249/100=
EXERCICE 4 :
B= ((7/4)-(3/4))×((7/5)+(2/5))
= 1×(9/5) = 9/5
C=(17/14)-((3/2)×(5/7))
= (17/14)-(15/14) = 2/14=1/7
D=((7/12)+(1/6))×(3/2)
= ((7/12)+(2/12))×(3/2)
= (9/12)×(3/2) = 27/24=9/8
EXERCICE 5 :
B= (2/5)×(13/7)+(2/5)×(1/3)
= (26/35)+(2/15)
= (390/525)+(70/525) = 460/525=92/105
C=12×((7/3)-(5/4))
= 12×((28/12)-(15/12))
= 12×(13/12) = 13
D=(3/10)×(7/2)-(3/4)×(9/5)
= (21/20)-(27/20)
= -6/20= -3/10
