You may also like

problem icon

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?

problem icon

Number Squares

Start with four numbers at the corners of a square and put the total of two corners in the middle of that side. Keep going... Can you estimate what the size of the last four numbers will be?

problem icon

I'm Eight

Find a great variety of ways of asking questions which make 8.

Number Round Up

Stage: 1 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

If you are a teacher, click here for a version of the problem suitable for classroom use, together with supporting materials. Otherwise, read on ...

Arrange the numbers $1$ to $6$ in each set of circles below.

The sum of each side of the triangle should equal the number in the centre of the triangular shape.

9 10

11 12

 

Once you've had a chance to think about it, click below to see how three different pupils began working on the task.

 

Dan said:

"I used counters which had $1$ to $6$ on them.

I put the counters in a triangle in any old way, then I added up the sides.

Then I moved the counters around to try and get the right total on each side."

 

Emma said:

"I noticed that three of the numbers are odd ($1, 3$ and $5$) and three of the numbers are even ($2, 4$ and $6$).  I thought this might help.

I know that $9$ is an odd number so it can be made using odd + odd + odd or using even + even + odd."

 

Farah said:

"If I want a small total on each side, I'll need small numbers in the corners of the triangle."

 

Can you take each of these starting ideas and develop it into a solution?

 

A practical version of this activity is included in the Year 3/4 Brain Buster Maths Box which contains hands-on challenges developed by members of NRICH and produced by BEAM. For more details and ordering information, please scroll down this page .