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Problematised Dino Situation

Published almost 2 years ago by Ann Baker

I was asked to do a demo lesson in a Year 1-2 class. The problem below was set into a story about my nephew who is dinosaur crazy and wants to make a dinosaur frieze. "He needs 12 of each of these dinosaurs which he drew himself. He wonders how many teeth he will have to draw and how many spike too. I said you would work it for him."


The class engaged very quickly and could project themselves into the situation. The range of responses was varied and each work sample provided insights into student thinking.

As a formative assessment task it revealed many strengths, ideas for next moves as well as some common error patterns.

The work sample below shows a typical approach to getting started.


Drawing the dinosaurs seems to buy thinking time because as you can see the student soon shifts focus to the teeth and finding a smart strategy for working out how many. The strategy itself is a step up from drawing and counting all the teeth.

This work sample shows a couple of typical developmental stages and a common error pattern.

Note that the top row of tallies are drawn and counted in 6s. The second row are drawn in 4s but counted in 3s giving an incorrect total for the teeth.

As part of a follow up strategy lesson a focus on making groups of 5 tallies with a counter underneath can be introduced to speed up counting (using the 5s counting pattern). Many students will soon notice that it is even quicker to count in 10s. The following quick sketch might give some ideas for an anchor chart that you can co create with your students.


Why not try this problem with your class? Download a copy here: dino1-download

Want to know more about problematised situations? Check out our new online course on this important element of the numeracy block.

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