Method minus

base/src/main/java/net/time4j/Moment.java:1479–1486

(
        long amount,
        SI unit
    )

     * @throws  ArithmeticException in case of overflow
     */
    public Moment minus(
        long amount,
        SI unit
    ) {

        return this.plus(Math.negateExact(amount), unit);

    }

    /**
     * <p>Subtracts given real time from this timestamp on the UTC time scale. </p>