setChildItem(Fraction.NUMERATOR, rednum);
setChild(Fraction.NUMERATOR, rednum);
    public void reduct() throws Exception {        Integer den = (Integer) getChildItem(Fraction.DENOMINATOR);                if (den != null) {                        Integer num = (Integer) getChildItem(Fraction.NUMERATOR);                        if (num != null) {                    Integer absnum = num.absolute();                                if (absnum != null) {                        // Find the biggest divider that both, numerator and denominator contain.                                    Integer max;                        if (absnum.isSmallerThanOrEqualTo((Integer) getChildItem(Fraction.DENOMINATOR))) {                            max = absnum;                                            } else {                                                max = (Integer) getChildItem(Fraction.DENOMINATOR);                    }                        Integer rednum;                                        if (max != null) {                        // Find the first divider with integer result (without rest).                        // Begin with the biggest divider that both, numerator and denominator contain.                        int i = max.getJavaPrimitive();                        while (i > 1) {                            if (absnum.isDividableWithoutRest(i) && den.isDividableWithoutRest(i)) {                                /*??                                rednum = absnum.divideBy(i);                                    if (num.isSmallerThan(0)) {                                                                        setChildItem(Fraction.NUMERATOR, rednum.multiplyWith(-1));                                                                    } else {                                                                        setChildItem(Fraction.NUMERATOR, rednum);                                }                                    setChildItem(Fraction.DENOMINATOR, den.divideBy(i));                                break;*/                            }                            i--;                        }                                    } else {                                                throw new Exception("Could not reduct fraction. The maximum divider is null.");                    }                }            }        }    }