### Homes

There are to be 6 homes built on a new development site. They could be semi-detached, detached or terraced houses. How many different combinations of these can you find?

### 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?

# Briefcase Lock

### Why do this problem?

This problem is a good context in which to encourage children to work systematically to find all possibilities.

### Key questions

If $8$ is the first digit, what numbers are possible?
What could be the first digit instead of $8$?
How do you know you have all the possibilities?

### Possible support

If children are struggling to find a system, invite them to write down different possible numbers on separate pieces of paper. Once they have thought of as many as they can, work with them to sort the numbers so that a pattern emerges and a structure is imposed. In this way, learners will be able to spot any gaps for themselves.