Myself and my colleague, Erica Richards, have created a series of Arithmagon activities covering 14 different maths topics. Okay, so they are no Venn Diagrams, but I believe they are a very worthwhile activity for the following reasons:

1) They are so simple to create and don’t require any special resources
2) Working forwards allows students to consolidate key mathematical concepts
3) Working backwards encourages deep mathematical thinking and creativity, hence effective differentiation
4) They are so versatile they can be used for pretty much any mathematical topic
5) Students can be set the challenge of creating them for a worthwhile extension task / homework

The whole set is available for free via this page.

I hope you and your students enjoy them!