Question

Folosind asociativitatea si comutativitatea,efectuati :

a) 1+( -2) + 3 + ( - 4) + 5 + (-6) + 7 + ( - 8 ) + 9 + ( - 10 )
................................................................................................
b) 1 +2 + (-2) +( - 4 ) + 5 + ( - 6) + 7 + (- 8) + 9 + ( -10) + (+11) +(-12).


VA ROG AM PANA LA 11:00

DAU SI COROANA

Answer 1

a) =(1-2)+(3-4)+(5-6)+(7-8)+(9-10) 
=-1-1-1-1-1=-5  si

=(1+3+5+7+9)+(-2-4-6-8-10)
=25-30=-5

b)=(1+2)+(-2-4)+(5-6)+(7-8)+(9-10)+(11-12)
=3-6-1-1-1-1=3-10=-7 si

=(1+2+5+7+9+11)+(-2-4-6-8-10-12)
=35-42=-7