Réponses

2014-04-07T20:14:57+02:00
a: 5/18 - (5/36 - 1/36)
= 5/18 - 4/36
= 5 x 2 / 18 x 2 - 4/36
= 10/36 - 4/36
= 6/36
=  6 x 1 / 6 x 6
= 1/6      

b: 17/12 - (11/12 - 1/3)
= 17/12 - (11/12 - 1 x 4 / 3 x 4)
= 17/12 - (11/12 - 4/12)
= 17/12 - (7/12)
= 10/12
= 2 x 5 / 2 x 6
= 5/6
           

c: 11/6 - 2/3 + 1/6
= 11/6 - 2 x 2 / 3 x 2 + 1/6
= 11/6 - 4/6 + 1/6
= 12/6 - 4/6
= 8/6
= 2 x 4 / 2 x 3
= 4/3    

d : 23/8 - 3/4 - 1/2
= 23/8 - 3 x 2 / 4 x 2 - 1 x 4 / 2 x 4
= 23/8 - 6/8 - 4/8
= 23/8 - 10/8
= 13/8 

Meilleure réponse !
2014-04-07T20:18:41+02:00
A) 5/18 - (5/36 - 1/36)
= 5/18 - 4/36
= 5x2 / 18x2 - 4/36
= 10/36 - 4/36
= 6/36
= 1x6 / 6x6
= 1/6

b) 17/12 - (11/12 - 1/3)
= 17/12 - (11/12 - 1x4 / 3x4)
= 17/12 - (11/12 - 4/12)
= 17/12 - 7/12
= 10/12
= 5x2 / 6x2
= 5/6

c) 11/6 - 2/3 + 1/6
= 11/6 - 2x2 / 3x2 + 1/6
= 11/6 - 4/6 + 1/6
= 7/6 + 1/6
= 8/6
= 4x2 / 3x2
= 4/3

d) 23/8 - 3/4 - 1/2
= 23/8 - 3x2/ 4x2 - 1x4 / 2x4
= 23/8 - 6/8 - 4/8
= 17/8 - 4/8
= 13/8