[tex]S = 2 + 4 + 6 + ... + 106[/tex]
[tex]S = 2(1 + 2 + 3 + ... + 53)[/tex]
[tex]S = 2 \times \frac{53(53 + 1)}{2} [/tex]
[tex]S = 53(53 + 1)[/tex]
[tex]S = 53 \times 54[/tex]
[tex]S = 2862[/tex]
[tex]Formul \check{a}\:: \: 1 + 2 + 3 + ... + n = \frac{n(n + 1)}{2} [/tex]
