ex 2
12/10 - 5/10 = (12-5) / 10 = 7/10
27/20 - 8/20 = (27-8) / 20 = 19/20
53/120 - 3/12 = 53/120 - 30/120 tu finis voir H et I
4/9 - 19/45 = 20/45 - 19/45 tu finis comme H et I
50/3 - 100/7 = 50x7/3x7 - 100x3/7x3 = 350/21 - 300/21 et tu finis
25/8 - 3 = 25/8 - 3x8/1x8 = 25/8 - 24/8
