Bonsoir
a. 5/9 + 2/9 = 7/9
b. 15/13 = (15 x 2) / (13 x 2) = 30/26
30/26 - 33/26 = - 3/26
c. 2/9 = (2 x 2) / (9 x 2) = 4/18
- 26/18 + 2/9 = - 22/18 et - 26/18 = (2 x - 13) / (2 x 9) = - 13/9
- 13/9 + 2/9 = - 22/18
d. 3 = (3 x 20) / (1 x 20) = 60/20
- 77/20 - (- 137/20) = 60/20
- 77/20 - (- 137/20) = 3.
