Bonjour,
A = 1/2 - 3/4 x 16/9
A = 1/2 - 48/36
A = (1 x 18) / (2 x 18) - 48/36
A = 18/36 - 48/36
A = - 30/36
A = (6 x - 5) / (6 x 6)
A = - 5/6
B = 1/5 - 3/10 x 1/6 + 3/2
B = 1/5 - 3/60 + 3/2
B = (1 x 12) / (5 x 12) - 3/60 + (3 x 30) / (2 x 30)
B = 12/60 - 3/60 + 90/60
B = 99/60
B = (3 x 33) / (3 x 20)
B = 33/20
C = (1/5 - 3/10) x (1/6 + 3/2)
C = [(1 x 2) / (5 x 2) - 3/10] x [1/6 + (3 x 3) / (2 x 3)]
C = (2/10 - 3/10) x (1/6 + 9/6)
C = - 1/10 x 10/6
C = - 10/60
C = (10 x - 1) / (10 x 6)
C = - 1/6.