Bonjour,
A = 1/9 + 15/9 x 1/6
A = 1/9 + 15/54
A = (1 x 6) / (9 x 6) + 15/54
A = 6/54 + 15/54
A = 21/54
A = (3 x 7) / (3 x 18)
A = 7/18
B = (11/15 - 1/6) x 5/6
B = [(11 x 2) / (15 x 2) - (1 x 5) / (6 x 5)] x 5/6
B = (22/30 - 5/30) x 5/6
B = 17/30 x 5/6
B = 85/180
B = (5 x 17) / (5 x 36)
B = 17/36
C = 5/2 x 15/4 - 2
C = 75/8 - (2 x 8) / (1 x 8)
C = 75/8 - 16/8
C = 59/8
