This is a game suggested by my daughter's 1st grade teacher, and I made a little variant.  It's fun to play and helps teach quick math skills.

It uses a standard deck of cards.

Put 6 cards face-up in the center (nobody has cards in their hand).

Kid goes first - try to "Make 10" by summing up the value of the cards.  A is 1, KQJT are each 10, so you can just say any of those cards and take it if they are face up.  9,1 will "Make 10".  So will "5,3,2"

Once you "Make 10", you get to keep those cards that you made 10 with.

If there's no way to Make 10, simply add 2 more cards to the face-up section in the middle.

Most cards at the end wins.