public ExtDecimal plus() {
        if (type == Type.NUMBER) {
            return new ExtDecimal(content.plus());
        } else if (type == Type.POSITIVEZERO) {
            return new ExtDecimal(Type.POSITIVEZERO);
        } else if (type == Type.NEGATIVEZERO) {
            return new ExtDecimal(Type.NEGATIVEZERO);
        } else if (type == Type.INFINITY) {
            return new ExtDecimal(Type.INFINITY);
        } else if (type == Type.NEGATIVEINFINITY) {
            return new ExtDecimal(Type.NEGATIVEINFINITY);
        } else {
            throw new UnsupportedOperationException("Unknown type");
        }
    }