public static function add($amountA, $amountB)
    {
        $precision = (int) self::config()->get('precision');
        if (function_exists('bcadd') && self::config()->get('useBcMath')) {
            return bcadd($amountA, $amountB, $precision);
        }

        return self::formatFloat((double)$amountA + (double)$amountB, $precision);
    }