Addition Step-by-Step Exercise without Regrouping http://www.dositey.com/addsub/add5a.html Addition Step-by-Step Exercise with Regrouping 1 http://www.dositey.com/addsub/as85/add3r.htm Addition Step-by-Step Exercise with Regrouping 2 http://www.dositey.com/addsub/as85/add5ar.htm Adding 2-Digit Numbers http://www.dositey.com/addsub/mystery2A.htm Adding 3-Digit Numbers http://www.dositey.com/addsub/add3dig.htm 3-Digit Addition Quiz without Regrouping http://www.numbernut.com/basic/activities/add_quiz_3nocarry-v.shtml 3-Digit Addition Quiz with Regrouping http://www.numbernut.com/basic/activities/add_quiz_3carry-v.shtml