Straightforward and short Python solution using regex and `fractions` module
With the fractions module, doing rational number arithmetic becomes really trivial.\n\n\nclass Solution(object):\n  def fractionAddition(self, expression):\n   
With the `fractions` module, doing rational number arithmetic becomes really trivial.\n\n```\nclass Solution(object):\n  def fractionAddition(self, expression):\n    """\n    :type expression: str\n    :rtype: str\n    """\n    import re\n    from fractions import Fraction\n    # Append + to start if first fraction is positive for easier parsing.\n    expression = ('+' + expression) if expression[0] != '-' else expression\n    splitted = re.split('([-|\\+]\\d+\\/\\d+)', expression)\n    splitted = [fragment for fragment in splitted if fragment.strip() != '']\n  \n    def parse_fraction(fraction):\n      sign = fraction[0]\n      numer, denom = [int(part) for part in fraction[1:].split('/')]\n      return Fraction(numer if sign == '+' else -numer, denom)\n  \n    result = 0\n    for fraction in [parse_fraction(part) for part in splitted]:\n      result += fraction\n    return "{}/{}".format(result.numerator, result.denominator)\n      \n```
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