Stage: 2 Challenge Level: 
How many different routes are there from S to T which do not go through either of the points U and V more than once?
If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.
This problem is taken from the UKMT Mathematical Challenges.
View the previous week's solutionMultiplication & division. Visualising. Combinations. Addition & subtraction. Practical Activity. Investigations. Route inspection problems. Mathematical reasoning & proof. Working systematically. Selecting and using information.
Published February 2012.
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