rig = (1..9).to_a
  lef = (1..9).to_a
  index = 0
  10.times do
    if lef[index] <= 9
      rig.each do |l|
       sum = lef[index] * l
      puts "#{lef[index]} × #{l} = #{sum}"
      if l == 9
        index+=1
      end
     end
    end
  end
