Have I mentioned my new addiction - Pinterest ?!  If you haven't tried it, you really should.  It's like being able to visit hundreds of classrooms and see what teachers have come up with.  (There are other topics there too:  food, beautiful places, quotes, you name it...)  Karen at Prekinders has given an excellent introduction for new "pinnners" on her blog. http://prekinders.com/2011/07/pinterest-for-teachers/ (Yes, I made the list of teachers who have been busy pinning....)  Anyway, I found this basic idea on Pinterest yesterday.  The source was http://secondinshawnee.blogspot.com/.  On that blog it was being used to match homophones (second grade).  It lends itself so well to Pre-K!  I picked up this puzzle at the Target Dollar Spot today.  I wrote matching upper and lower case numbers with a Sharpie and it's ready to go.  (The puzzle has 36 pieces, so some pieces are left blank).