What is the difference between the sum of the squares and the square of sums?

euler-005.rb

#!/usr/bin/env ruby

# The sum of the squares of the first ten natural numbers is,
# 12 + 22 + ... + 102 = 385
# The square of the sum of the first ten natural numbers is,
# (1 + 2 + ... + 10)2 = 552 = 3025
# Hence 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 natu-
# ral numbers and the square of the sum.
# 
# Solution:

a,b,c = 0,0,0
(1..100).each do |x|
  a += x ** 2
  b += x
end
b = b ** 2
c = b - a
puts c