# World of Tan 26 - Old chestnut

Can you fit the tangram pieces into the outline of the brazier for roasting chestnuts?

## Problem

This activity follows on from World of Tan 25 - Pentominoes.

**Granma T:**Oh dear! It's only Monday and the children are arguing already!

Little Fung and Little Ming are sitting at the table, trying to solve a puzzle.

**Little Fung:**It can be done!

**Little Ming:**No it can't! Our teacher showed us that at the end of the lesson.

**Granma T:**Why are you making all this noise? Do either of you have any homework to do? If not, get out into the yard, there's plenty to do there! Help the workers tidy up.

**Little Fung:**Not that old chestnut again!

**Granma T:**Pardon?

**Little Ming:**Little Fung asked about old chestnuts!

**Little Fung:**That's right. What are they? What does it mean?

**Granma T:**Go outside and finish off out there - we can talk about this later!

The children go outside into the yard to help with the tidying up. Granma T rejoins Mah Ling back in the office.

**Granma T:**What was all that nonsense about 'old chestnuts'?

**Mah Ling:**I'm not sure but I feel certain that over your meal tonight you'll be questioned about it. The children like having answers, and they're not afraid to ask.

**Granma T:**That's a good thing. And I know they ask a lot of questions at school. Their teacher must get exhausted!

**Mah Ling:**When I was at school, no-one was allowed to speak unless spoken to.

**Granma T:**The times are changing, Mah Ling. Even the schoolwork that the children do is so much more interesting and more demanding than the work you or I did at school. They are encouraged to think for themselves.

**Mah Ling:**We're certainly kept busy with all the problems that the children bring home!

**Granma T:**I wonder what it will be tonight?

**Mah Ling:**It might be something about language? All that fuss about old chestnuts...

The two children come back into the house noisily.

**Little Fung:**It can be done!

**Little Ming:**No it can't. Don't you ever learn?

**Granma T:**And on and on they go until dinnertime!

In the meantime, complete the silhouette of a brazier used to roast chestnuts.

Extra activity:

- Can you resolve Little Ming and Little Fung's argument? Here is their diagram:

The story continues in World of Tan 27 - Sharing.

## Teachers' Resources

### Why do this problem?

This problem is an engaging context in which pupils can consolidate their knowledge of the properties of squares, triangles and parallelograms. By attempting this activity, children will be putting into practise their visualising skills, making guesses about where the different shapes might go before trying out their ideas. When combining the shapes to make the tangram, pupils will use their understanding of translations, reflections and rotations to decide how to transform each shape. There are also links between tangrams and fractions, and children can be encouraged to work out what fraction of the whole square is represented by each smaller shape.### Possible approach

Read this story with the whole class and look at the tangram as a group. Ask pupils to suggest where a shape might go. What transformation would be needed to move the shape into that position?When pupils are solving the tangram, they would benefit from working in pairs with a tablet or a printed copy of the shapes to cut out and move around. Working together will lead to rich discussions about the possible options for where each shape can go. When the children have solved the tangram, they can have a go at the extra activities.

At the end of the lesson, bring all of the pupils together and model the solution on the whiteboard. How does each shape need to be transformed? What fraction of the whole picture is each shape?

### Key questions

What could you put with this piece to make a square?Are all of the pieces different?

What's the smallest square you can make?

What has to go in that space? How do you know?