Réponses

2014-01-30T17:08:50+01:00
4/7 - 2      =      4/7 - 2 x 7 / 1 x 7    =    4/7 -14/7    = -7/7 = -7/7 x 14/17 = 98/119
2 - 11/14      2 x 14 / 1 x 14 - 11/14    28/14 - 11/14  17/14