src/org/kocakosm/pitaya/math/Fraction.java
public Fraction minus(Fraction f)
	{
		return new Fraction(n.multiply(f.d).subtract(f.n.multiply(d)),
			d.multiply(f.d)).reduced();
	}
public Fraction minus(Fraction f)
	{
		return new Fraction(n.multiply(f.d).subtract(f.n.multiply(d)),
			d.multiply(f.d)).reduced();
	}
Subtracts the given value from this one and returns the result in
reduced form.

@param f the fraction to subtract from this one.

@return {@code this - f} in reduced form.

@throws NullPointerException if {@code f} is {@code null}.