Question

Calculați prin doua metode sumele de mai jos iar apoi comparați rezultatele.Model:Metoda 1) a) (-3)+(+5)+(-9)+(+1)=+2+(-9)+(+1)=-7+(+1)=-6 Metoda 2) a) (-3)+(+5)+(-9)+(+1)=[(+5)+(+1)]+[(-3)+(-9)]=(+6)+(-12)=-6 c) (+5) + (-6)+(-8)+(+12) d) (+19)+(+9)+(-12)+(-16) e) (-13)+(-14)+(+12)+(+10) f) (-2)+(+1)+(+1)+(-4) g) (+3)+(+4)+(-16)+(+2) h) (-4)+(+3)+(+7)+(-9)

Answer 1

c).5-6-8+12=3
+5+12-6-8=17-14=3

d).19+9-12-16=0
19+9-12-16=28-28=0

e)-13-14+12+10=-5
-13-14+12+10=-27+22=-5

f).-2+1+1-4=-4
-2-4+1+1=-6+2=-4

g).3+4-16+2=-7
3+4+2-16=9-16=-7

h).-4+3+7-9=-3
-4-9+3+7=-13+10=-3