A little ruby script to get sum of all digits reduced to one, given an array of random numbers between an interval.

summarizer.rb

random = Random.new

lower = 1000000000
upper = lower * 2 - 1

numbers = 10.times.collect { random.rand(lower..upper) }

summarizer = lambda do |number|
  array = number.to_s.split("").collect(&:to_i)

  array.inject { |sum, i| sum += i }
end

numbers.each do |number|
  sum = total = summarizer.call(number)

  stack = []
  stack << number
  stack << total

  if sum < 10
    stack << sum
  else
    new_sum = sum

    loop do
      new_sum = summarizer.call(new_sum)

      stack << new_sum

      break if new_sum < 10
    end
  end

  puts stack.join(" - ")
end

Muito bom! :D