Rational & operator=(const Rational & r) {P = r.P; Q = r.Q; Simplify(); return *this;}
Rational & operator+=(const Rational & r) {this->operator=(*this+r); return *this;}
Rational & operator-=(const Rational & r) {this->operator=(*this-r); return *this;}
Rational & operator*=(const Rational & r) {this->operator=(*this*r); return *this;}
Rational & operator/=(const Rational & r) {this->operator=(*this/r); return *this;}
Rational & operator=(const Rational & r) {P = r.P; Q = r.Q; Simplify(); return *this;}
Rational & operator+=(const Rational & r) {this->operator=(*this+r); return *this;}
Rational & operator-=(const Rational & r) {this->operator=(*this-r); return *this;}
Rational & operator*=(const Rational & r) {this->operator=(*this*r); return *this;}
Rational & operator/=(const Rational & r) {this->operator=(*this/r); return *this;}