Réponses

2014-04-07T21:22:24+02:00
1/9=?/54 = 6*1 / 6*9 = 6/54
6/10=?/40 = 6*4 / 4*10 = 24/40
8/7=?/63 = 9*8 / 9*7 = 72/63