Bonjour

A = 14/27 - (1 x 9) / (3 x 9)

A = 14/27 - 9/27

A = 5/27

B = 12 x [5/8 - (1 x 2) / (4 x 2)]

B = 12 x (5/8 - 2/8)

B = 12 x 3/8

B = 36/8

B = (4 x 9) / (4 x 2)

B = 9/2

C = (13 x 4) / (15 x 4) - 12/60

C = 52/60 - 12/60

C = 40/60

C = (20 x 2) / (20 x 3)

C = 2/3.