You HAVE to visit it. Here. It has a variety of figures and it can be used to encourage talking about mathematics in the classroom. Initially, I was thinking it would be an excellent warm-up for my high schoolers, just to get them thinking and comfortable since there are no right or wrong answers. Then today, I was working one-on-one with one of my 1st grade ELL students and I thought I should show him this. He was very interested. I showed him the following image from the website:
I asked him "Which one is different?" and it took him some time to realize there wasn't a right or wrong answer. We went through each box and he said how each one was "different."
The 1st graders responses, roughly translated:
Top left - upside-down
Top right - not a triangle
bottom left - slanted
bottom right - looks like a ramp
How amazing is that?? What an excellent discussion! Then he was ready for more. He really wanted a numbers one, so we did this next:
Responses:
Top left - 3 digits
top right - only box with a 6 in it
bottom left - only one digit
bottom right - if you had the digits together, you get 10.
I thought I was dreaming when my student then asked how we could add 73 and 16. Umm, you want to learn how to do double-digit addition because of mere curiosity? Absolutely, let's learn! And that's how my day started. It was very nice and I'll definitely return to this website for many years.

