Under CCP 400, a mandate petition attacking an order denying a motion to change venue must be filed within 20 days after service of notice of judgment (plus 5 days if service is by mail). Here, the clerk served the challenged order by mail on May 12. The last day to file the petition was 25 days later, or Monday, June 7. The petition was not filed until June 11 and so was untimely. The clerk’s certificate of mailing met CCP 1013a’s requirements. The clerk’s mailing of notice was effective and started the 20-day deadline even though CCP 1019.5 requires the prevailing party to serve notice of an order granting or denying a motion.