When I first made these, it was to play Uno with my eldest daughter. Then my middle daughter started sorting them out into colored piles, and the next day I found her at 7 am sorting them into different number groups and I ended up making a ton of games out of the cards.
They make great flash cards, or for playing War to reinforce which number is bigger.
These versatile cards are bright and easy to read. And depending how you use them they could be used from Pre-K right through to 5th or 6th grade and beyond as a version of the card game Uno.
I included 3 different math center signs and storage bag identification cards so that you can print and use whichever one is better for your needs, or you can print extra cards out and make multiple games and not worry about sharing the cards between them and risk losing them.