Stage: 1 Challenge Level: 
Why do this problem?
This problem is one that requires working systematically
because it is necessary to try and improve as you find the way
through the network. It is also a good activity for promoting
discussion between learners working together. This sheet , which can be
photocopied, gives two copies of the network for working on.
Key questions
Why don't you make a list of the numbers from $1$ to $9$ and
cross them out as you go?
Which number can you not use until the end?Possible extension
Children who do this quickly could find other ways through the
network. Can they find all the possible ways?
Possible support
You could suggest crossing out all the numbers from which you can't start. This sheet gives two copies of the network for working on.Introducing algebra. Visualising. Factors and multiples. Counting. Games. Working systematically. Addition & subtraction. Multiplication & division. Interactivities. Trial and improvement.
Published February 2002.
Copyright © 2007. University of Cambridge. All rights reserved.
NRICH is part of the family of activities in the Millennium Mathematics Project, which also includes the Plus and Motivate sites.
email: nrich@damtp.cam.ac.uk