211      * @param int $scale
214     private function add($s1, $s2, $scale)  argument
217             return bcadd($s1, $s2, $scale);
219             return $this->scale((float)$s1 + (float)$s2, $scale);
227      * @param int $scale
230     private function mul($s1, $s2, $scale)  argument
233             return bcmul($s1, $s2, $scale);
235             return $this->scale((float)$s1 * (float)$s2, $scale);
243      * @param int $scale
246     private function div($s1, $s2, $scale)  argument
249             return bcdiv($s1, $s2, $scale);
251             return $this->scale((float)$s1 / (float)$s2, $scale);
279             return $this->scale(round($n, $sigfigs - $new_log - 1), $rp + 1);
286      * @param int $scale
289     private function scale($r, $scale)  argument
291         if ($scale < 0) {
299             $precise = (string)round(substr($r, 0, strlen($r) + $scale), -1);
301             return substr($precise, 0, -1) . str_repeat('0', -$scale + 1);
303         return sprintf('%.' . $scale . 'f', (float)$r);