Copyright © University of Cambridge. All rights reserved.

'Noughts and Crosses' printed from http://nrich.maths.org/

Show menu

Now play Tic Tac Toe (Noughts and Crosses). If you play correctly you never lose and if your opponent plays correctly you cannot win.

If you can see this message Flash may not be working in your browser
Please see http://nrich.maths.org/techhelp/#flash to enable it.

Look at all of these games. What do you notice about the strategies they employ?

We suggest tackling them in the order given.