public function quotient($that) : BigInteger
    {
        $that = BigInteger::of($that);

        if ($that->value === '1') {
            return $this;
        }

        if ($that->value === '0') {
            throw DivisionByZeroException::divisionByZero();
        }

        $quotient = Calculator::get()->divQ($this->value, $that->value);

        return new BigInteger($quotient);
    }