Magnetic number Fishing. They add what they catch.--older kids can multiply to make it more difficult. Or could practice making fractions where the first number pulled is the numerator and the denominator is the bottom, then they have to say it correctly!
The kids loved watching bean seeds sprout. We put five beans in a ziploc bag with a folded wet paper towel. The bags were taped to our classroom window (with names written in permanent marker). Of course we also read "Jack and the Beanstalk