Explications étape par étape:

A = (12/3 - 2/3)(6/3 - 4/3)

A = 10/3 × 2/3

A = 20/9

B = 3/4 - (1/4 ÷ 5/2) la division est prioritaire.

B = 3/4 - (1/4 × 2/5)

B = 3/4 - 2/20

B = 15/20 - 2/20

B = 13/20