Aidée moi s'il vous plaît

A = 4/5 + 2/3
A = 4 x 3 / 5 x 3 + 2 x 5 / 3 x 5
A = 12/15 + 10/15
A = 22/15

B = 1/5 - 6/3
B = 1 x 3 / 5 x 3 - 6 x 5 / 3 x 5
B = 3/15 - 30/15
B = - 27/15
B = 3 x - 9 / 3 x 5
B = - 9/5

C = 5/4 - 7/8 - 2/9
C = 5 x 18 / 4 x 18 - 7 x 9 / 8 x 9 - 2 x 8 / 9 x 8
C = 90/72 - 63/72 - 16/72
C = 11/72

D = 5/2 x 4/7
D = 10/14
D = 2 x 5 / 2 x 7
D = 5/7

E = 6/7 : 5/2
E = 6/7 x 2/5
E = 12/35

F = 5/2 : (3/5 x 4/3)
F = 5/2 : (12/15)
F = 5/2 x 15/12
F = 75/24
F = 3 x 25 / 3 x 8
F = 25/8