Question

4. Calculati: a) 2+( - 4 ) + 15 +( - 9 ) si ( 2 + 15 ) + ( - 9 ) ;
b) ( 3 + 5 + 1 ) + 3 + ( - 5 ) + 1 + 3 + 5 + ( - 1 ) + ( - 3 ) + 5 +1 .
5.Calculati : a) ( 1 + 2 + 3 ) + 1 + 2 + ( - 3 ) + 1 + ( - 2 ) + ( - 3 ) + ( - 1 ) + (- 2 ) + ( - 3 ) ;
b) - 8 - 11 + ( - 3 ) + 7 + ( - 1 ) si ( 11 + 7 ) + ( - 8 ) + ( - 3 ) + ( - 1 ) .

Answer 1

a.
2+( - 4 ) + 15 +( - 9 )=2-4+15-9=17-13=4
( 2 + 15 ) + ( - 9 ) =17-9=8

b.( 3 + 5 + 1 ) + 3 + ( - 5 ) + 1 + 3 + 5 + ( - 1 ) + ( - 3 ) + 5 +1 =
9+3-5+9-1-3+6=12+4-4+6=16+2=18

5.
a. ( 1 + 2 + 3 ) + 1 + 2 + ( - 3 ) + 1 + ( - 2 ) + ( - 3 ) + ( - 1 ) + (- 2 ) + ( - 3 ) =
6+3-3+1-2-3-1-2-3=9-2-5-6=7-11=-4

b. - 8 - 11 + ( - 3 ) + 7 + ( - 1 )=-19-3+7-1=-22+6=-16
( 11 + 7 ) + ( - 8 ) + ( - 3 ) + ( - 1 ) =18-8-3-1=10-4=6

Answer 2

4.a)2+(-4)+15+(-9)
=2-4+15-9
=4
(2+15)+(-9)
=17-9
=8
b)(3+5+1)+3+(-5)+1+3+5+(-1)+(-3)+5+1
=3+5+1+3-5+1+3+5-1-3+5+1
=18
5.a)(1+2+3)+1+2+(-3)+1+(-2)+(-3)+(-1)+(-2)+(-3)
=1+2+3+1+2-3+1-2-3-1-2-3
=-4
b)-8-11+(-3)+7+(-1)
=-8-11-3+7-1
=-16
(11+7)+(-8)+(-3)+(-1)
=11+7-8-3-1
=6