first_solution.rb

def zero(method = nil)
  calculate(method, 0)
end
def one(method = nil)
  calculate(method, 1)
end
def two(method = nil)
  calculate(method, 2)
end
def three(method = nil)
  calculate(method, 3)
end
def four(method = nil)
  calculate(method, 4)
end
def five(method = nil)
  calculate(method, 5)
end
def six(method = nil)
  calculate(method, 6)
end
def seven(method = nil)
  calculate(method, 7)
end
def eight(method = nil)
  calculate(method, 8)
end
def nine(method = nil)
  calculate(method, 9)
end
def calculate(method, value)
  method ? eval("#{value} #{method}") : value
end
def plus(value)
  "+ #{value}"
end
def minus(value)
  "- #{value}"
end
def times(value)
  "* #{value}"
end
def divided_by(value)
  "/ #{value}.to_f"
end