Project Euler Problem 4: Find the largest palindrome made from the product of two 3-digit numbers.

euler_4.rb

def palindrome
  palindromes = []

  (999).downto(100).each do |number|
    (number ..999).each do |range_of_numbers|
      product = number * range_of_numbers
      if product.to_s == product.to_s.reverse
        palindromes << product
      end
    end
  end
  palindromes.max
end