Réponse :
Bonjour
Explications étape par étape
A) 3×7 = 21
4×7=28
=>21/28
B) 2×8=16
5×8 = 40
=>16/40
C) 6×5 = 30
7×5 = 35
=>30/35
D) 5×8 =40
8×8 = 64
=>40/64
Ex3)
A) 25/40=5×5/8×5=5/8
B) 15/18=5×3/6×3=5/6
C) 14/6=7×2/3×2=7/3
D) 110/20=11×10/2×10=11/2