Réponse :
Explications étape par étape :
Exercice 1 :
A = 7 + 3/4 = 28/4 + 3/4 = 31/4
B = -15/49 x 28/-35 = 420/1715 = 12/49
C = 3 - 1/2 X 4/3 = 3 - 4/6 = 18/6 - 4/6 = 14/6 = 7/3
D = 3 X 4/12 = 12/12 = 1
Exercice 2 :
E = 7/5 + 3/5 x 11/6 =7/5 + 33/30 = 42/30 + 33/30 = 75/30 = 5/2
F = -3/-5 x -10/9 + 5/3 = 30/-45 + 5/3 = 30/-45 + -75/-45 = -45/-45 = 1
G = (3 - 24/5) x -10/3 = (15/5 - 24/5) x -10/3 = -9/5 x -10/3 = 90/15 = 6
Exercice 3 :
a. 1/2 x 1/2 = 1/4
b. 1/4 x 1/3 x 1/2 = 1/24
c. 30/100 x 2/5 = 60/500 = 6/50 = 3/25
d. 2/5 x 5/7 x 21 = 210/35 = 6
Exercice 4 :
3/4 x 3/5 = 9/20
Exercice 5 :
1. Pour le cadet : 2/3 x 3/4 = 6/12 = 1/2
2. Pour le benjamin : 1 - 1/3 - 1/2 = 6/6 - 2/6 - 3/6 = 1/6
3. 1/6 pour le benjamin < 1/3 pour l'ainé < 1/2 pour le cadet.
