If you've ever had a sleepless night, or bout of insomnia, then you know the horribleness that is lying awake at night. It always feels like the harder you try to pass out, the more elusive sleep…MoreMore *** Read more at the image link.
Can differentiate with double digits (double digit by double digit multiplication or even fractions). This site has great math projects. This can be done with nails in a board and colored yarn. Makes a great pricture too.