public static Fraction operator +(Fraction a, Fraction b)
{
long gcd = Fun.GreatestCommonDivisor(a.Denominator, b.Denominator);
long aDenomDivGcd = a.Denominator / gcd;
return(new Fraction(
a.Numerator * (b.Denominator / gcd)
+ b.Numerator * aDenomDivGcd,
aDenomDivGcd * b.Denominator
));
}