public function toBest($precision = null)
    {
        $fromUnit = UnitResolver::resolve($this->from);
        $base = $this->getBase() == 2 ? 1024 : 1000;
        $converted = $this->start;
        while ($converted >= 1) {
            $fromUnit++;
            $result = $this->div($this->start, pow($base, $fromUnit), $precision);
            if ($result <= 1) return $converted;
            $converted = $result;
        }
        return $converted;
    }