# So it's 28

Here is your chance to investigate the number 28 using shapes,
cubes ... in fact anything at all.

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I've just found that I keep coming
across the number $28$.

Next Year's calendar for
February:

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then there's my set of $28$ dominoes:

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So, why don't you explore this number? Find $28$ flat shapes the same and put them together in some way.

Here are some I found using circular discs, octagons, hexagons, triangles and pentagons.

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You may like to try $28$ cubes and
get something like this:

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or put together to make a
caterpillar with changes at the ends.

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Let us know what you come up with
and what you notice.

Perhaps you can find $28$ things to investigate. How
about counters or cubes or sticks or ...?

We had very few ideas sent in but it seems that most pupils went on to the other challenge focussed on $28$: $28$ and It's Onwards and Upwards.

Matthew wrote the following and sent in the picture to go with it:

I used $28$ tessellating crosses, which are on the file. Looks quite cool. The scary thing is, after copying and pasting $28$ crosses (having just made them a random size), I, co-incidentally, couldn't fit any more than $28$ on the page ...

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and Emma wrote:

I got grid paper and drew $14$ squares that were touching and drew a line diagonally through every square. I got $28$ triangles because I had $14$ squares and split them in $2$ which made $28$ because $14+14=28$. That is how I got $28$ triangles.

**Why do this problem?**

This activity is good for allowing pupils to explore both shapes and number, or to choose a particular aspect to focus on. There is a lot of freedom involved and there are exciting things to find out. Learners will be able to take control of their own learning and choose their own direction in this task.

### Possible approach

You could begin by showing some of the pictures in the problem on the screen for the pupils to see and talk about. What similarities do they notice? What differences? They may pick up on the fact that the common link is the number $28$ straight away, but if not you can ask questions to probe them further. If some would like more examples they can be found here.

You can then set the group off on their own ideas using the number $28$. Pupils should be encouraged to ask themselves questions like " I wonder what would happen if I ...?", making a small change and exploring further.

### Key questions

Tell me about what you've got here.

Is there anything special about this shape you have made?

Can you find another arrangement?

### Possible extension

Talk about symmetry and look for final shapes that are symmetrical and those that are asymmetric.

Children who are used to investigating and have done well with this may like to move on to 28 - Upward and Onward.

### Possible support

There may be a need for help with those with less developed fine motor skills for moving the shapes and fitting them together. Magnetic shapes can sometimes help.