On Fridays we estimate. I had been pulling all of my estimation tasks from Estimation180.com until this happened a couple weeks ago:
We did that exponential growth/decay activity with M&M’s. A great task for a wacky schedule due to standardized testing. At one point, a student looked into his cup and said, “Does that look like 97 M&M’s?” Another kid said, “No way! I would have guessed that was more like 30.” The first kid then wondered aloud how many candies are in the packs you buy. Then he suggested we do some estimation tasks with M&M’s.
Kids were better able to apply their background knowledge to this since just two days before they'd spent a lot of time counting M&M's and putting them in a cup.
I wish I remember why we talked about the volume of a cylinder... Oh! One student got out a ruler and measured one M&M and the width of the container. He tried to justify his estimate based on those two measurements but his justification didn't make any sense (I really don't remember what that was). So we talked about how you could use the information he measured to make a better estimate using that equation, but we didn't do any actual calculations.
Once we were done discussing a student asked if she could count. She came up to the front of the room and carefully counted out all thirty-six candies. Usually my students are reasonably quiet while we're engaged in a discussion but start chatting as soon as there's a lull. They were so quiet as she counted! Occasionally a student made a relevant comment - Darn! I was too low! - but mostly they just watched and listened to her count. Engagement accomplished.