July 5, 2014

This is a fun and simple game that lends itself to a variety of math topics, including 1- and 2-digit addition, place value, absolute value, and negative numbers. It’s great for practicing mental math and combinations to make 10. It also provides many great opportunities to have math talks to discuss strategy. My students love this game. It’s easy to learn, there’s no time pressure, and it’s not as directly competitive as other games can be, which helps some students thrive more.

**>>>CLICK HERE FOR A PRINTER-FRIENDLY VERSION WITH THE SCORING TEMPLATE AND INSTRUCTIONS.<<<**

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**Math Skills Covered:** Addition (2-digit numbers), place value, negative numbers (optional), combinations to make 10**Materials: **Deck of cards, scoring sheet**
# of Players: **2+

Grades:

**OBJECT OF THE GAME: **Get the lowest overall score in the game by adding two 2-digit numbers to get as close to 100 as possible.

**Prepare the deck:
**Prepare your deck by removing all face cards (J, Q, K) from the deck. (Leave Aces and 10’s in.)

**Special card values:**

Aces = 1

10’s = 0

**HOW TO PLAY:**

- Deal out 6 cards per player.

- Each player selects 4 cards from their hand to make
**two**2-digit numbers that add up to 100, or as close as they can get to it.

*What combinations can Tiffany make with the numbers 2, 6, 2, 7, 9, 4?*

*62+42=104*

*29+ 67=96*

*…Ah-hah! 76 + 24 = 100! Perfect!*

- Players write down numbers and sum on score sheet. The score is how far away you are from 100. Since Tiffany’s total was exactly 100, she gets a score of 0!

- When both players are ready, they share their solutions and check each other’s work.
- Repeat for rounds 2-5.

In the examples below, try looking at the cards on the left and come up with combinations closest to 100 before looking at my solutions on the right.

Round 2:

*Oops, I just realized that I should have added 74 with 26 (instead of 28). Um. Let’s pretend I did that on purpose… because you see, this would be a great opportunity to discuss strategies with your child, such as noticing that your score is over by a bit, and reminding them to check if there is a way to lower it… =P*

Round 3:

Round 4:

*In this case, I could have done 8***3**+18, which would give me a score of 101. Both options add 1 to my score, so it doesn’t matter. However, if I were scoring with negatives (see in “Variations” section below), then 99 vs. 101 would actually matter.

Round 5:

- At the end, add up all the points to get their
*Total Score*.

- The lowest score wins.

**>>>CLICK HERE FOR A PRINTER-FRIENDLY VERSION WITH THE SCORING TEMPLATE AND INSTRUCTIONS.<<<**

**FAQ**

Q: Can I use just one card to make a 1-digit number?

A: No. The only way to make a 1-digit number is if you have a zero (remember, 10’s = 0 in this game), such as “0 7” in Round 3 above.

Q: What if I have all high cards, like all 8’s and 9’s?

A: You will have a really high score… 🙁

Q: What do I do when there are no more cards in the deck?

A: Shuffle all of the used cards and keep going.

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**Variations:**

*Make it more challenging:*Students can use negative numbers to calculate their score instead of absolute value. For example, a sum of 97 means they are*under by 3*, so the score would be -3. A score of 103 would result in +3 (or just plain “3”). This will change the strategy in the game! You can see the difference in scoring below.

*Make it easier:*Deal 4 cards (instead of 6) and add up 1-digit numbers to get to 10. That is, instead of a goal of

__ __ + __ __ = 100,

make it a goal of

__ + __ = 10*Save paper:*If you don’t have the printout on hand, you can still easily play this game and just compete one round at a time. Experiment with using just one hand and seeing who can come up with the best combination first (this makes it more competitive).

**Discuss Strategies**

Just like in the game Tic-Tac-Toe Products (and most other games), there’s a great opportunity for learning in discussing strategy. Here are some possible things to look for and/or discuss with your child:

*What’s your strategy?*Do you look for numbers that will get you close to 100 by starting with the tens place? Ones?*How do you add the numbers in your head?*What others ways can you add them?- Consider this hand: 1, 3, 4, 5, 5, 6
- Perhaps your child makes the combination 65 + 45. Maybe she is using her knowledge of combinations for 10 (adding 6 and 4) to make a combination for 100. That’s a good first step. Try to help her discover that since she is over 100, she could make her sum closer by choosing smaller numbers in the ones place, using the combination 61 + 43. This reduces the final sum by 6.
- Even better, help your child see that even though 6+4=10, that doesn’t mean one should necessarily always use the 6 and 4 combination (or any other combination for 10). For example, with this hand, 65 and
can be used to make exactly 100. Discuss how if you go**3**5*over*60, then you might try to compensate with the second number by going*under*by the same amount.

- If you are playing the challenging version, ask about strategies used at various points in the game. For example, Larry was dealt a very bad hand in Round 3, and ended up with 37 points!

Before proceeding, ask him, “What should your strategy be from here? Should you still try to make your cards add up to 100?” Try to guide him to see that to get to an*overall total score*of 0 in the end, it’s better in this round to aim for something closer to 60, so that the negative points can cancel out the +37 points. For example:

In this situation, 41+21=62 is actually preferable to 57+42=99 because it brings the total score closer to 0.

I hope you give this fun and easy game a try! It’s great mental math practice and of course kids have a ton of fun when you play together with them! Family game night, anybody?

See more fun math games in my series on *Fun Math Games for Children!*

Love to get new math games with cards! Thank you!

You’re welcome! Isn’t it great how cards are so versatile?

Ooh, this looks fun!

It is! =D