The sum of the squares of the first ten natural numbers is,

1^{2}+ 2^{2}+ … + 10^{2}= 385The square of the sum of the first ten natural numbers is,

(1 + 2 + … + 10)^{2}= 55^{2}= 3025Hence the difference between the sum of the squares of the first ten natural numbers and the square of the sum is 3025 385 = 2640.

Find the difference between the sum of the squares of the first one hundred natural numbers and the square of the sum.

My solution in Java:

public class Euler6 { private long sumOfSquares() { long total = 0; for ( int i = 1; i < 101; i++) { total += i*i; } return total; } private long squareOfSums() { long total = 0; for ( int i = 1; i < 101; i++ ) { total += i; } return total*total; } public long answer() { return squareOfSums() - sumOfSquares(); } }