Bonjour
A = 12/4 + 2/6 - 3/8
A = (12 x 3) / (4 x 3) + (2 x 2) / (6 x 2) - (3 x 3) / (8 x 3)
A = 36/12 + 4/12 - 9/12
A = 40/12 - 9/12
A = 31/12
B = 5/3 - (- 4/5) + 1/15
B = (5 x 5) / (3 x 5) + (4 x 3) (5 x 3) + 1/15
B = 25/15 + 12/15 + 1/15
B = 38/15
C = - 6/3 - (4/- 9) + 25/12
C = (- 6 x 12) / (3 x 12) + (4 x 4) / (9 x 4) + (25 x 3) / (12 x 3)
C = - 72/36 + 16/36 + 75/36
C = - 72/36 + 91/36
C = 19/36
D = 4/7 + 3/4 - 2/5
D = (4 x 20) / (7 x 20) + (3 x 35) / (4 x 35) - (2 x 28) / (5 x 28)
D = 80/140 + 105/140 - 56/140
D = 80/140 - 161/140
D = - 81/140.
