Explications étape par étape:
Bonjour,
a) 15/25 = 5x3/5x5
= 3/5
b) 90/60 = 3x30/2x30
= 3/2
c) 63/81 = 7x9/9x9
= 7/9
d) 132/144 = 11x12/12x12
= 11/12
