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Hunter0Killer
a fost răspuns

Calculaţi:
a) 10+20+30+40+...+90=...................
b)100+200+300+...+1000=...............
c)2222+4444+6666+8888=............
d)11111+22222+33333+...+99999=...

Răspuns :

a)10+20+30+...+90=
  10(1+2+3+...+9)=
 10* 10*11/2=
 10*55= 550

b)100+200+300+...+1000=
100(1+2+3+...+10)=
100* 10* 11/2=
100*5*11= 5500

c)2222+4444+6666+8888=
2222(1+2+3+4)=
2222* 4*5/2=
4444*5=22220

d)11111+22222+33333+....+99999=
11111(1+2+3+....+9)=
11111*9*10/2=
99999*5=499.995
RalucaAndreea10
a) 10(1+2+...+9)=
10*(9*10:2)=
10*45=450
b) 100(1+2+...+9)=
100*(9*10/2)=
100*45=4500
c) 1111(2+4+6+8)=
1111*20=22220
d) 1111(1+2+...+9)=
1111*(9*10:2)=
1111*45=49995
Sper ca te-am ajutat!