In this 3 minute video, Dedra Wright demonstrates how to teach students about the mean as a balance point. She models this concept using a number line and blocks which are manipulated throughout the activity. In the video, two data sets are shown as models and then connected to the written algorithm. A companion video, Introduction to the Concept of the Mean: Mean as Fair Share, is cataloged separately as a related resource.
I had always heard of mean as fair share, but I had not heard of it being used as the "balance point" before. I like that this activity gives students another opportunity to build the conceptual framework for Mean.
Good technique but not connected By Uncle Bob on 11/13/2012 - 14:29
... not connected to the formula for mean. By adjusting a pair of entries (blocks) down one and up one, the sum of the set is preserved. Students need to see the moves as math justified and not as a trick. Once that is established the blocks can be moved down and up 2 or 3.