Remembering 10

I sometimes think that great mathy moments with my kids must require a certain amount of planning and preparation. But they don’t. Not always. The following version of the simple game Memory is familiar but with a twist to reinforce your child’s recall of 10 addition facts.

Here’s what to do:

1. Get a deck of regular playing cards.
2. Pull out all the face cards and the 10’s. Put them to the side.
3. Divide the remaining cards into their suits, and choose just two suits to play with. (So now you should have 20 cards left in hand. Ace, 1, 2,…,9 of two suits.)
4. Shuffle the cards and place them face down in a 4 x 5 grid. (And while you’re doing that…why not point out to your child the 4 x 5 dimensions? Why not verbalize that 4 groups of 5 equals 20 and 5 groups of 4 equals 20? Why not wonder if it’s possible to create a different grid of 20 cards that doesn’t have dimensions 4 by 5?)
5. Take turns flipping two cards over. If the cards add to 10, you have a match! If they do not add to 10, turn them back over.
6. That’s it. Easy. After you’ve played a few times, you might add the other suits in to the game for a 40 card challenge. (What are the possible dimensions for a grid of 40 cards?)

Tips for playing:

1. When YOU flip the cards, pause for a couple extra moments before announcing the sum of your two cards. This will give your child time to consider the sum herself. She might even call the answer out before you do, feeling she has beat you to the punch!
2. If your child is getting too caught up in the competition of who has the most winning pairs, make the game cooperative. Pile the successfully paired cards into one common pile. Let your child help you remember where to find the matching cards. Celebrate your wins together.
3. After playing with 20 cards, make the game even more challenging by bringing back the other two suits for a 40-card game. (What are the possible dimensions for a grid of 40 cards?) You can also add in the 10’s if you pick another card (Jokers maybe) to represent 0.

(Mathematically…knowing what numbers add to 10 is a cornerstone skill for taking on arithmetic with larger numbers. If you know that 8 + 2 = 10, then you can figure out 38 + 2 = 40. This is also the foundation for being able to quickly calculate 8 + 6 by splitting that 6 into 2 and 4 then adding the 2 to the 8 to make 10. Add the remaining 4 and the answer is 14. Once you can do that, you can do 38 + 6 the same way. This technique of mental manipulation and flexibility is much more efficient than “counting on” with fingers or drawings or manipulatives. To put that into context…I have tutored kids in upper elementary or middle school who are adept at processes like multiplication or division of large numbers – they can set the numbers up and carry correctly.  Unfortunately, the work takes them a very long time to complete because they are counting on their fingers to add single digit numbers together. Playing card games and board games with your kids while they are young helps build flexibility with these single digit numbers.)