fluent.rb

class Calc
  NUMBERS = %w[one two three four five six seven eight nine ten]

  def initialize(number = 0, meth = nil)
    @number = number
    @meth = meth
  end

  NUMBERS.each_with_index do |number, index|
    define_method(number) do
      value = index + 1

      if @meth
        @number.send(@meth, value)
      else
        value
      end
    end
  end
end

class Fixnum
  OPS = { plus: :+, minus: :-, times: :*, divided_by: :/ }

  OPS.each do |op, meth|
    define_method(op) { Calc.new(self, meth) }
  end
end