I actually learned how to use the Venn Diagram for Lowest Common Multiples. When you are finding LCM of two numbers, you write what is common to both numbers into the overlapping section, the remaining factors in the circle for the number then multiply the factors together.
As you can see the factors for the LCM are 7 x 2 x 11 x 2 x 2 if you read left to right. This is a way for my students to see the difference between GCF and LCM and they have trouble telling the two apart.
This could easily be done on doodle buddy or SAS Gloss or some other program which would allow them to use their fingers.
I am thinking that you could have a venn diagram in pdf form and send it to the kids so they use annotation to do the work. Opens up some new possibilities.