Bonjour
A= 3/14 + 5/21
A = (3 x 3) / (14 x 3) + (5 x 2) / (21 x 2)
A = 9/42 + 10/42
A = 19/42
B= 3/4 + 2/5 x 10/3
B = 3/4 + 20/15
B = (3 x 15) / (4 x 15) + (20 x 4) / (15 x 4)
B = 45/60 + 80/60
B = 125/60
B = (5 x 25) / (5 x 12)
B = 25/12
C= -8/45 x 27/32
C = - 216/1440
C = (72 x - 3) / (72 x 20)
C = - 3/20
D= 5/3 - 2/3 : 7/4
D = 5/3 - 2/3 x 4/7
D = 5/3 - 8/21
D = (5 x 7) / (3 x 7) - 8/21
D = 35/21 - 8/21
D = 27/21.
D = (3 x 9) / (3 x 7)
D = 9/7.
