euler/euler006.rb

def sumSquared(n)
  (1..n).inject(:+) ** 2
end

def squareSums(n)
  sum = 0
  for i in 1..n
    sum += i ** 2
  end
  sum
end

def difference(n)
  sumSquared(n) - squareSums(n)
end

puts squareSums(10)
puts sumSquared(10)

puts difference(100)