Réponses

2014-03-31T18:50:07+02:00
1/2 + 3/2 x 7/5
= 1/2 + 21/10
= 1x5 / 2x5 + 21/10
= 5/10 + 21/10
= 26/10
= 2x13 / 2x5
= 13/5

20/9 - 5/3 x 2/3
= 20/9 - 10/9
= 10/9

5/3 + 10/21
= 5x7 / 3x7 + 10/21
= 35/21 + 10/21
= 45/21
= 3x15 / 7x3
= 15/7