The Ultimate Guide to Hands On Toddler Activities - Brittany Estes--- This could also work for pre-math skills. Which shape has more or less? I would put on magnets on the back and have a magnetic work space for them to do this activity!
Come learn an easy trick that will get you the most dramatic, puffy, foamy baking soda and vinegar eruptions and learn the science behind it! From Fun at Home with Kids. Baking soda and vinegar mixed with a tough of soap.