Réponses

2013-05-02T19:49:20+02:00
-4,5-2,5+7=-7+7=0

c) 3,8+2,2+4,5=6+4,5=10,5

d) 13,7-3,7+20-25=10+20-25=30-25=5
2013-05-02T19:50:04+02:00

a)(-4.5)+(-2.5)+7

=(-7)+7

=0

c)3.8+(+2.2)+(4.5)

=6+(4.5)

=10.5

d)(+13.7)+(-3.7)+(+20)+(-25)

=10.7+20+(-25)

=30.7+(-25)

=5.7