Estimation Jar: A lesson in reasonableness

Reasonableness is an important skill to incorporate into your lessons.  One easy way to do this is through an estimation jar.  I have organized estimation jars different ways.

Method #1: Students-in-charge:
  • Star student is in charge of supplying materials to put in our estimation jar.
  • Math Wizard is in charge of supplying materials to put in our estimation jar.
Method #2: Teacher-in-charge:
  • Set up an estimation jar that is part of our bell work.  For a week, I put the same thing in the jar but a different amount each day.  I begin with things that are similar size and shapes like unifix cubes and wooden cubes.  After doing similar shapes for a couple of weeks, I put in something that is smaller, like the small base-10 unit cubes.  We discuss if the unifix cubes is bigger than the base-10 units, on Monday of last week our estimation jar was half full and this week our estimation jar is half full, what would be a reasonable estimate for how many base-10 units are in our jar?  Would there be more or less than last week?  Remember our cubes this week are smaller so will more fit in the same amount of space or less?  What is a reasonable estimate? 

You can easily add a seasonal twist to your estimation jar.  I got these Halloween colored plastic rocks at Hobby Lobby.

Some shapes are more challenging than others.  Do you have a really bright class this year that needs a challenge?  Add feathers to your estimation jar.  They are fun to use at Thanksgiving and they will give your students a challenge.

Are you looking for some new estimation jar lessons?  Click HERE to download my FREE Lesson in a Jar packet.

Sources to make my blog post graphics can be found HERE.

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