Réponses

2013-12-04T12:34:21+01:00
A= 1/3 + 5/4
=4/12+15/12
=19/12

B= 3/7 - 10/21
=9/21-10/21
=-1/21

C= 15/28 x 7/25 x 1/6
=3/4 x 1/5 x 1/6
=1/4 x 1/5 x 1/2
=1/40

D= -2-(7/-21 - -7/-8 )
=-2+7/21+7/8
=-2+1/3+7/8
=-2+8/24+21/24
=-48/24+29/24
=-19/24

E= -7/15 + 3/20
=-28/60+9/60
=-19/60