Bonjour
A = 2/3 - 1/6 = (2 x 2) / (3 x 2) - 1/6 = 4/6 - 4/6 = 3/6 = (3 x 1) / (3 x 2) = 1/6
B= 2/3 + 7/30 = (2 x 10) + (3 x 10) + 7/30 = 20/30 + 7/30 = 27/30 = (3 x 9) / (3 x 10) = 9/10
C = 17/18 - 1/6 = 17/18 - (1 x 3) / (6 x 3) = 17/18 - 3/18 = 15/18 = (3 x 5) / (3 x 6) = 5/6
D = 1/21 + 2/3 = 1/21 + (2 x 7) / (3 x 7) = 1/21 + 14/21 = 15/21 = (3 x 5) / (3 x 7) = 5/7
1) 5/2 + 2/5 = (5 x 5) / (2 x 5) + (2 x 2) / (5 x 2) = 25/10 + 4/10 = 29/10
2) 6/7 + 1/2 = (6 x 2) / (7 x 2) + (1 x 7) / ( 2 x 7) = 12/14 + 7/14 = 19/14
3) 3/5 - 1/4 = (3 x 4) / (5 x 4) - (1 x 5) / (4 x 5) = 12/20 - 5/20 = 7/20
4) 7/12 + 2/3 = 7/12 + (2 x 4) / (3 x 4) = 7/12 + 8/12 = 15/12 = (3 x 5) / (3x 4) = 5/4
5) 10/3 - 1/6 = (10 x 2) / (3 x 2) - 1/6 = 20/6 - 1/6 = 19/6.
