Find the difference between the sum of the squares and the square of the sum

gistfile1.rb

#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 natural numbers and the square of the sum

ruby-1.9.2-p180 :004 > (1..10).to_a.reduce(:+)**2 - (1..10).to_a.map { |x| x**2 }.reduce(:+)
 => 2640 
ruby-1.9.2-p180 :005 > (1..100).to_a.reduce(:+)**2 - (1..100).to_a.map { |x| x**2 }.reduce(:+)
 => 25164150