Sorting activities are great to help children build math skills. As they create patterns, organize items in sets and examine similarities and differences in items, they build a foundation for a better understanding of math. This is a fun and inexpensive sorting activity for your grandchildren to do when they come to visit. It’s really great for all ages. Sometimes my adult children get involved. I put all kinds of interesting items in my jar. There are buttons, plastic money, beads, plastic animals, rocks, marbles, the list is endless! I dump the jar onto the table then the children begin organizing their favorite items. I like to talk to them about what they chose and why, what other items match what they already have. They usually come up with answers that I would have never had thought of. To keep things from falling on the floor, dump the items into a large box lid. You could use an egg carton for sorting the items.