Without calculator

Algebra Level 2

$1^2+2^2+3^2+4^2+5^2+6^2+7^2+8^2+9^2+10^2+11^2+...+2015^2=?$

2729148240 1989044343 2713344450 2348974588

1 solution

Paola Ramírez
Dec 2, 2015

A sum squares is given by the formula $\frac{n(n+1)(2n+1)}{6}$ where $n$ is the last square number

$\therefore$

$1^2+2^2+3^2+...+2015^2=\frac{2015(2016)(4031)}{6}=\boxed{2729148240}$