code: @Override
      public Geldbetrag remainder(Number divisor) {
          return Geldbetrag.valueOf(betrag.remainder(toBigDecimal(divisor, context)), currency);
      }
docs: Returns a {@code MonetaryAmount} whose value is <code>this % divisor</code>.
  <p>
  The remainder is given by
  <code>this.subtract(this.divideToIntegralValue(divisor).multiply(divisor)</code> . Note that this
  is not the modulo operation (the result can be negative).
  </p>
  
  @param divisor value by which this {@code MonetaryAmount} is to be divided.
  @return {@code this % divisor}.
  @throws ArithmeticException if {@code divisor==0}, or if the result exceeds the numeric capabilities of this
  implementation class, i.e. the {@link MonetaryContext} cannot be adapted as
  required.