Aidez moi svp ex 12 math

Bonjour,

Calcule et donne le résultat :

A = 5 x 2/3 - 1/3
A = 10/3 - 1/3
A = 9/3
A = 3

B = 7/4 - 3/4 x 3/2
B = 7/4 - 9/8
B = (7x2)/(4x2) - 9/8
B = 14/8 - 9/8
B = 5/8

C = (5/6 + 7/12) x 3/5
C = [(5x2)/(6x2) + 7/12] x 3/5
C = (10/12 + 7/12) x 3/5
C = 17/12 x 3/5
C = 3/12 x 17/5
C = 1/4 x 17/5
C = 17/20

D = 3/4 x 2/9 + 28/15 x 25/14
D = 3/9 x 2/4 + 28/14 x 25/15
D = 1/3 x 1/2 + 2 x 5/3
D = 1/6 + 10/3
D = 1/6 + (10x2)/(3x2)
D = 1/6 + 20/6
D = 21/6