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What makes a Good Resource - 3’s and 5’s

This page has been archived. The content was correct at the time of original publication, but is no longer updated.
Created on 26 August 2010 by ncetm_administrator
Updated on 03 September 2010 by ncetm_administrator

What Makes a Good Resource

3’s and 5’s

Resource description:

3’s and 5’s

This is an investigation activity which uses only simple addition bonds. It is easily accessible, promotes pairs / small group work and can be extended to engage further thinking, talk and reasoning.

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Teacher comment:

This has worked well, engaging pupils in mainstream SEN and MLD settings.

What I did:

Pupils were asked what answers you could make if you only used numbers 3 and 5 and the only operation was addition. Working in pairs, they tried to find which “answers” below 20 were possible. After 10 minutes we checked and shared. Pairs who were not able to find a number got this from another pair and vice versa.


A few things emerged from this activity.

  • Some pairs carried on past 20. They joined up into larger groups and found that all the “answers” were possible
  • I asked how far we could go until we found an impossible “answer”. Pairs reported that the highest impossible number was 7.
  • It was very satisfying when a child offered that all answers were possible after 20, reasoning that if you could make 11, you can make 21 by adding two 5’s; if you could make 12, you can make 22, 32, etc by adding 5’s, and so on.
  • Some asked about using other pairs [e.g. 4’s and 7’s, 3’s and 8’s, etc]. They wanted to see whether 7 was still the highest impossible answer.   It wasn’t!!....but that is a whole new adventure.

From small beginnings came a very rich activity.

Special Educational Needs

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