bjr
-1/2 + 1/5 = -5/10 + 2/10 = -3/10 ok
-1/7 + 3/5 = -5/35 + 21/35 = 16/35 ok
-1/2 + 5/3 = - 3/6 + 10/6 = 7/6 ok
5/10 - 3/6 = 1/2 - 1/2 = 0 pour moi
9/8 - 5/12 = 27/24 - 10/24 = 17/24 pour moi
multiple commun de 8 et 12 = 24..
7/9 - 2/15 = 35/45 - 6/45 = 29/45
multiple commun de 9 et 15 = 45
