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  • John Sasko

    November 30, 2020 at 2:09 pm

    On Monday morning you had 11 of your favorite red jellybeans. By lunch time you had 7 red jellybeans. How many red jellybeans did you eat?

    This is “change unknown” or missing subtrahend. It is a subtraction problem. Students might use a part/part/whole diagram, or counting on with a number line (or counting backwards) or the balance model.

    I would like to see the balance model used more than it is! (I have encouraged teachers I support to use these concrete tools and they always are surprised that it works!!!!)

    When we were in brick and mortar (and not remote) I had a balance out on my bookshelf for co-workers to see and play with any time they wanted to. Now that we are remote I have encouraged teachers to use a virtual manipulative balance. ( has a decent one that is free to use.) It is such a great algebraic thinking tool that is under-appreciated.