Question

Calculati :
a) 2+(-4)+15+(-9) si (2+15)+(-4)+(-9)
b) -8+11+(-3)+7+(-1) si (11+7)+(-8)+(-3)+(-1)
P.S DAU 50 DE PUNCTE

Answer 1

a)
2+(-4)+15+(-9)=
2-4+15-9=
(-2)+6=
6+(-2)=
6-2=
4

(2+15)+(-4)+(-9)=
17-4-9=
13-9=
4=

b)-8+11+(-3)+7+(-1)=
11-8-3+7-1=
3-3+6=
0+6=
6

(11+7)+(-8)+(-3)+(-1)=
18-8-3-1=
10-3-1=
7-1=
6