### Let's Investigate Triangles

Vincent and Tara are making triangles with the class construction set. They have a pile of strips of different lengths. How many different triangles can they make?

### Teddy Town

There are nine teddies in Teddy Town - three red, three blue and three yellow. There are also nine houses, three of each colour. Can you put them on the map of Teddy Town according to the rules?

### Noah

Noah saw 12 legs walk by into the Ark. How many creatures did he see?

# Homes

## Homes

As this sign shows there are to be 6 homes built on a new development site. Houses are often put into three groups. Perhaps you live in one of these:-

• Semi-detached houses
• Detached Houses
• Terraced houses

You probably know that detached houses are built separately with no joining to another house. Semi-detached houses are ones in which two are joined together so all the houses appear in pairs. When there are three or more houses together they're called terraced. You are asked to decide on how many of these you would use. So you might suggest:- 1 detached + 2 semi-detached (you have to have an even number of these since they come in pairs) + 3 terraced ( you have to have 3 or more of these). The order does not matter. We are just counting up what we've got. Suppose you use a short hand to record this and have the following key:-

D : Detached

S : Semi-detached

T : Terraced



you might record this first arrangement as:- D S S T T T and this is the same as S S T T T D for this challenge.

You don't have to use all three kinds each time, you might have:-

T T T T T T or

S S D D D D etc



Well, what different collections of homes can you find?

Have you been using a system for this?

So, once you've got that, what about the question, "I wonder what would happen if there were 7 ( 8, 9 or 10 ) homes?"

Try these and see how you get on.

You might like to ask "I wonder what would happen if S S S S D D is taken to be different from S S D D S S ?" What does this produce when you're trying to find all these arrangements? You might like to try this alternative with a smaller number of homes first. So you might try 4 homes, and start off:-

D D D D

S S D D

D S S D

D D S S


but you cannot have S D D S as the two semi-detached have to be next to each other.

Well have fun with these and good luck !

### Why do this problem?

This activity is particularly good for the younger children. It starts them off with some freedom with regards to the way that they record what they are suggesting as solutions. The arithmetic involved is number bonds to six but very few children see it as this at first!

### Possible approach

It might be a good idea to allow different physical arrangements of the same types of houses to be allowed, particularly if you decide to encourage the children to do some kind of drawing for their record keeping.

This investigation is also a good catalyst for discussion with small groups of children or with individuals, to find out how they are thinking and to encourage them to adopt a systematic approach.

### Key questions

Can you find a way of being sure that you've found all the ways?