Réponses

2012-09-23T15:52:58+02:00

A= 11-31= -20

 

B= -15-6= -21

 

C= 12-8-18+5

  = 12+5 -8-18

  = 17 -26 = -9

 

D= 4-(-7)= 4+7=11

 

E= -3-(+7)

  = -3 +7

  = 4