# Difference Of Squares

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

The square of the sum of the first ten natural numbers is
(1 + 2 + ... + 10)² = 55² = 3025.

The sum of the squares of the first ten natural numbers is
1² + 2² + ... + 10² = 385.

Hence the difference between the square of the sum of the first
ten natural numbers and the sum of the squares of the first ten
natural numbers is 3025 - 385 = 2640.

## Making the Test Suite Pass

1. Get [PHPUnit].

        % wget --no-check-certificate https://phar.phpunit.de/phpunit.phar
        % chmod +x phpunit.phar

2. Execute the tests for an assignment.

        % phpunit.phar wordy/wordy_test.php

[PHPUnit]: http://phpunit.de


## Source

Problem 6 at Project Euler [http://projecteuler.net/problem=6](http://projecteuler.net/problem=6)

## Submitting Incomplete Solutions
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