Question

qual a soma dos 20 primeiros numeros pares positivos ?

Answer 1

Os números são: 2,4,6,8,10,12,14,16,18,20,22,24,26,28,30,32,34,36,38,40.
Somando todos o resultado é: 420

Answer 2

2+4+6+8+10+12+14+16+18+20+22+24+26+28+30+32+34+36+38+40

(2+4+6+8)+(10+12+14+16)+(18+20+22+24)+(26+28+30+32)+(34+36+38+40)

      20       +        52             +    84               +         116          +      148

                                            total = 420