This excellent ActivBoard flipchart includes 9 Mathematical activities asking pupils to reveal and discuss which is the odd one out, using a range of images from dice to dominos, to different coins and jigsaw shapes.

The flipchart can be found here:
http://www.prometheanplanet.com/uk/server/show/ConResource.13735

If you are not yet a member of Promethean Planet, you will first have to register here:
http://www.prometheanplanet.com/uk/server/show/nav.914

If you want to view the activities and have some interactivity with them, but you don't have the ActivStudio software, you can download the free Viewer from here:
http://www.mypromethean.com/uk/server/show/ConWebDoc.2974