gistfile1.rb

class ErrorRounder
  def initialize
    @error = 0.0
  end

  def round(x, n=0)
    out = (x - @error).round(n)
    @error += out - x
    out
  end
  
  def self.split(total, items, n=0)
    e = new
    Array.new(items) { e.round(total.to_f/items, n) }
  end
end

a = ErrorRounder.split 101, 3, 2
p a
p a.inject(:+)