Bonjour
A = 3/8 + 2/5
A = (3 x 5) / (8 x 5) + (2 x 8) / (5 x 8)
A = 15/40 + 16/40
A = 31/40
B = 4/7 - 8/5
B = (4 x 5) / (7 x 5) - (8 x 7) / (5 x 7)
B = 20/35 - 56/35
B = - 36/35
C = 3/5 x 7/11
C = 21/55
D = 3/5 : 7/11
D = 3/5 x 11/7
D = 33/35
E = 1/3 + 2/5 x 3/4
E = 1/3 + 6/20
E = (1 x 20) / (3 x 20) + (6 x 3) / (20 x 3)
E = 20/60 + 18/60
E = 38/60
E = (2 x 19) / (2 x 30)
E = 19/30
F = (1/3 + 2/5) x 3/4
F = [(1 x 5) / (3 x 5) + (2 x 3) / (5 x 3)] x 3/4
F = (3/15 + 6/15) x 3/4
F = 9/15 x 3/4
F = 27/60
F = (3 x 9) / (3 x 20)
F = 9/20.
