def gcd(a, b)
  a %= b
  a == 0 ? b : gcd(b, a)
end

class Fraction
  def initialize(num, den)
    @num = num
    @den = den

    simplify
  end

  class << self
    private def simplify
      frac_gcd = gcd(@num, @den)

      @num /= frac_gcd
      @den /= frac_gcd
    end
  end
end

test = Fraction.new(5, 2)
puts test.num

# + adds
# - subtracts
# / divide
# * multiply
# s sqrt
# % mod
# a set vars to stack
# g sets stack to numbers
# q pushes value of stack to numbers
# i incrament
# d decrament
# r stops subtraction at 0
# w turns back on subtraction past 0
# [ starts loop
# ] ends loop runs until stack is 0
# { starts loop
# } ends loop and loops until loops[ln] is 0
# k incrament loops
# . prints ascii value of stack (starts at a=1)
# , adds ascii value of stack to stri
# > prints stri
# < prints stack
# _ prints ascii stack starting at 48

Traceback (most recent call last):
  File ".code.tio", line 13, in <module>
    print r(input()) == r(input())
  File ".code.tio", line 11, in r
    while y-a:a,y=y,s(y)
TypeError: unsupported operand type(s) for -: 'list' and 'list'

>>> (5==5)==5
False
>>>

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'Girl' is not defined