public function additiveInverse(): Decimal
    {
        if ($this->isZero()) {
            return $this;
        } elseif ($this->isNegative()) {
            $value = \substr($this->value, 1);
        } else { // if ($this->isPositive()) {
            $value = '-' . $this->value;
        }

        return new static($value, $this->scale);
    }