Répondre :
a) 3/7 + 16/35 = 3x5/7x5 + 16/35 = 15+16/35 = 31/35.
b) 4/35
A ) 3 / 7 = 3 x 5 / 7 x 5 = 15 / 35
15 / 35 + 16 / 35
31 / 35
B ) 35 / 35 - 31 / 35 = 4 / 35
15 / 35 + 16 / 35
31 / 35
B ) 35 / 35 - 31 / 35 = 4 / 35