Bonjour, pouvez vous m'aider: voilà le devoir . Merci d'avance
Donnez le résultat sous la forme la plus simple.

1/2+2/3+3/4+4/5+5/6

1/2-1/3+1/4-1/5+1/6

1/2-(1/3+1/4)-(1/5+1/6)


(2/3-1/6):(1/8-3/5)

13/4-(7/6-3/4)

(3/2-7/5)x(-5/6)-3

(3/4-2/7-2)x21/4

2/3+5/3x12/7-18x7/27

1

Réponses

2013-10-31T12:13:16+01:00
= 1/2 + 2/3 + 3/4 + 4/5 + 5/6
= 3/6 + 4/6 
+ 3/4 + 4/5 + 5/6
= 7/6 + 3/4 + 4/5 + 5/6
= 12/6 + 3/4 + 4/5
= 48/24 + 18/24 + 4/5
= 66/24 + 4/5
= 11/4 + 4/5
= 55/20 + 16/20
= 71/20 

= 1/2 - 1/3 + 1/4 - 1/5 + 1/6
= 3/6 - 2/6 + 1/4 - 1/5 + 1/6
= 1/6 + 1/4 - 1/5 + 1/6
= 2/6 + 1/4 - 1/5
= 8/24 + 6/24 - 1/5
= 14/24 - 1/5
= 23/60

= 1/2 - ( 1/3 + 1/4 ) - ( 1/5 + 1/6 ) 
= 1/2 - 7/12 - 11/30
= -1/12 - 11/30
= -9/20

= ( 2/3 - 1/6 ) : ( 1/8 - 3/5 )
= 1/2 : (-19/40)
= 1/2 x (-40/19)
= -20/19

= 13/4 - ( 7/6 - 3/4 )
= 13/4 - 5/12
= 17/6

= ( 3/2 - 7/5 ) x ( -5/6 ) - 3
= 1/10 x ( -5/6 ) - 3
= -1/12 - 3
= -37/12

= ( 3/4 - 2/7 - 2 ) x 21/4
= ( 13/28 - 2 ) x 21/4
= -43/28 x 21/4
= -129/16

= 2/3 + 5/3 x 12/7 - 18 x 7/27
= 2/3 + 20/7 - 14/3
= 74/21 - 14/3
= -8/7