Stage: 3 and 4 Challenge Level: 
Try working backwards.
Fibonacci sequences might help.
Play GOT IT and try to find a strategy for winning at this game.
Visualising. Mathematical induction. Trial and improvement. Complex numbers. Golden ratio. Mathematical reasoning & proof. Games. Fibonacci sequence. Making and proving conjectures. Interactivities.
Published January 2005,January 2007.
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