public function to($unit, $precision = null)
    {
        $fromUnit = UnitResolver::resolve($this->from);
        $toUnit = UnitResolver::resolve($unit);
        $this->setBase($unit);
        $base = $this->getBase() == 2 ? 1024 : 1000;
        //some funky stuff with negative exponents and pow
        if ($toUnit > $fromUnit)
            return $this->div($this->start, pow($base, $toUnit - $fromUnit), $precision);
        return $this->mul($this->start, pow($base, $fromUnit - $toUnit), $precision);
    }