This 24 slide PowerPoint presentation thoroughly explains the process of estimating with addition and subtraction. It reviews rounding and provides students with interactive practice and independent practice. There are notes for students and teachers. Real life estimation problems help students master the concept of estimation by using key words and rounding to problem solve. The lesson wraps up with test practice. This presentation was created by Elizabeth Hill and is currently used in her third grade classroom.
See my website at http://tricksoftheteachingtrade.blogspot.com for songs, videos, and other activities that I use in my classroom.