One of these things is not like the others,

“One of these things is not like the others,One of these things just doesn't belong,..”

(Lyrics by Raposo)

This charming song from Sesame Street was the first thing I thought of when I saw Which One Doesn’t Belong? .  Choose from numbers, graphs, shapes or you can even complete your own sets. The best thing about the site?  They don’t provide the answer (yet you can submit a response with your justification).  I think this would be perfect to engage student in thinking and would work well with a projector. (For the complete post from TeachersFirst, please click here.)