WC_Tax::precision PHP Method

    private static function precision($price)
    {
        return $price * pow(10, self::$precision);
    }

 /**
  * Load options.
  *
  * @access public
  */
 public static function init()
 {
     self::$precision = WC_ROUNDING_PRECISION;
     self::$round_at_subtotal = 'yes' === get_option('woocommerce_tax_round_at_subtotal');
 }