Choose two or three table tops that are shaped very differently but are all close in size.
Make your best guess at which is the smallest, which is the largest, and which is the middle one if you chose three.
Cover the one you think is the smallest with post it notes. Feel free to cut them if necessary to cover the entire surface.
Now cover the next smallest one with those same post it notes. Do you need more? Yes and you’re right it’s larger. No, and you are now covering the smaller table.
Take pictures, especially of your faces if you guessed wrong, and send them to me at ellen@9QMath.com
Too easy, arrange every surface at home and then go about measuring them in the same way to see how good your guessing is getting.