Here is a fun idea I picked up from Pinterest and made it my own. You can do this with unused or recycled Easter Eggs. I used them for adding doubles and other simple addition problems. I used different colors as suggested from one of my colleagues. This is so students wouldn't match them by color. This made it more challenging.
This is another enriching activity. My campus bought these rubbing plates. I decided to use them as an extension activity after they are done with their assignments in their centers. It is fun and reinforces what they learned. The rubbing Plates are from LakeshoreNumbers&CountingMathrubbing plates