very very easy

Algebra Level 2

the sum of the first 100 squares is ...


The answer is 338350.

Math Man by math man , 20, Indonesia

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2 solutions

1 2 + 2 2 + 3 2 + 4 2 + ⋯ + n 2 = n ( n + 1 ) ( 2 n + 1 ) 6 1^2+2^2+3^2+4^2+\dotsm+n^2=\frac{n(n+1)(2n+1)}{6} 1 2 + 2 2 + 3 2 + ⋯ + 10 0 2 = 100 ( 100 + 1 ) ( 2 ( 100 ) + 1 ) 6 1^2+2^2+3^2+\dotsm+100^2=\frac{100(100+1)(2(100)+1)}{6} 100 ( 101 ) ( 201 ) 6 = 100 ( 20301 ) 6 = 2030100 6 = 338350 \frac{100(101)(201)}{6}=\frac{100(20301)}{6}=\frac{2030100}{6}=\boxed{338350}

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1x1+2x2+...+nxn=n(n+1)x(2n+1)/6

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