checkNumber: (newValue) =>
    if @sex() is ''
      @number('?')
      return

    fullDate = newValue.toString()

    escaped  = fullDate.replace(/[^0-9]+/gi, '')

    fullYear = escaped.substr(escaped.toString().length - 4, 4)
    halfYear = escaped.substr(escaped.toString().length - 2, 2)

    escaped  = @getMagicNumber(halfYear)

    switch @sex()
      when 'f'
        escaped += 5
        escaped += 1 if (+fullYear) >= 2000
      when 'm'
        escaped  = 10 - escaped
        escaped -= 1 if (+fullYear) >= 2000

    escaped = @getMagicNumber(escaped)

    @number(escaped)

  getMagicNumber: (number) =>
    result = 0

    number = number.toString().replace(/[^0-9]+/gi, '')

    for char in number
      result += (+char)

    return @getMagicNumber(result) if result > 9

    result