Bonjour
A = 2/3 + 3/5
A = (2 x 5) / (3 x 5) + (3 x 3) / (5 x 3)
A = 10/15 + 9/15
A = 19/15
B = 3/2 - 2/3 x 5/3
B = 3/2 - 10/9
B = (3 x 9) / (2 x 9) - (10 x 2) / (9 x 2)
B = 27/18 - 20/18
B = 7/18
C = 15/39 x 26/25 x 28/42
C = 10 920/40 950
C = (2 730 x 30) / (2 730 x 15)
C = 30/15
D = (3 + 5/4) : (5 - 2/7)
D = [(3 x 4) / (1 x 4) + 5/4] : [(5 x 7) / (1 x 7) - 2/7]
D = (12/4 + 5/4) : (35/7 - 2/7)
D = 17/4 : 33/7
D = 17/4 x 7/33
D = 119/132
