Bonsoir , Qui peu aider et m' expliquer merci mon devoir

A = 5/18-(5/36-1/36)
A = 5/18-(4/36)
A = 5/18-1/9
A = 5/18-2/18
A = 3/18
A = 1/6

B = 17/12-(11/12-1/3)
B = 17/12-(11/12-4/12)
B = 17/12-7/12
B = 10/12
B = 5/6

C = 11/6-2/3+1/6
C = 12/6-2/3
C = 2-2/3
C = 6/3-2/3
C = 4/3

D = 23/8-3/4-1/2
D = 23/8-6/8-4/8
D = 23/8-10/8
D = 13/8