Réponses

2014-10-25T17:55:36+02:00
1/3 - 1/4
= 1 x 4 / 3 x 4 - 1 x 3 / 4 x 3
= 4/12 - 3/12
= 1/12

1/4 - 1/5
= 1 x 5 / 4 x 5 - 1 x 4 / 5 x 4
= 5/20 - 4/20
= 1/20

1/999 - 1/1000
= 1 x 1000 / 999 x 1000 - 1 x 999 / 1000 x 999
= 1000/999000 - 999/999000
= 1/999000

1/2 x 3 + 1/1000
= 3/2 + 1/1000
= 3 x 500 / 2 x 500 + 1/1000
= 1500/1000 + 1/1000
= 1501/1000