*Photo by Håkan Dahlström via flickr.*

**Math concepts:** addition and subtraction within 100, logical strategy

**Number of players:** 2 or 3

**Equipment:** printed hundred chart (also called a *hundred board*) and beans, pennies, or other tokens with which to mark numbers — or use this online hundred chart

## Set Up

Place the hundred chart and a small pile of tokens where both players can reach them.

## How to Play

Allow the youngest player choice of moving first or second; in future games, allow the loser of the last game to choose. The first player chooses any number from 1 to 15 and places a token on that square of the hundred chart.

On each succeeding turn, the player adds either 5, 10, or 15 to the most recently marked number and places a new token on his sum. Play alternates until no more tokens can be placed.

## Endgame

The player who places the last legal token (on one of the squares from 96-100) wins the game.

## Variations

**1 — **Allow players to add any number from 1 to 20 on each turn. The player who reaches 100 wins the game.

**2 — Count Down:** Start at 100 and subtract 5, 10, or 15 per turn. The player who reaches zero wins the game.

**3 — Mental Math:** Try the game (or either variation above) without a hundred chart, keeping track of the numbers in your head.

## Comments

Nim is a traditional folk game of uncertain origin (similar games are played in many places around the world), and it has always been a favorite at our Math Club meetings. This version of Nim gives young children a chance to build fluency with double-digit arithmetic, an important foundation for their future study of mathematics.

This post is an excerpt from my book *Addition & Subtraction: Math Games for Elementary Students*, available now from your favorite online book dealer.

Want to help your kids learn math? Claim your free 24-page problem-solving booklet, and you’ll be among the first to hear about new books, revisions, and sales or other promotions.

This looks like a fun game to play. Thanks, I think that I’ll give this a try w/my kids.

Thanks! I’d never have thought of playing Nim on a hundred chart. There are lots of potential variants.

I’ve made one up to play with my six year old (she already does two-digit subtractions in her head, so this will just be a bit of fun for her). I’ll toss it in our big box of games.

I think that my 1st grader will really enjoy this and we’ll take it over to our friend’s house on our combined-class days for game time.

I can’t wait to try this with my first grader! We’ve used a hundred chart before and am glad to have more activities to do with it.

I enjoyed playing the games your posted yesterday together with my friends so I am back to learn more of the games you posted and I think this one is also a fun game.

Hi, thanks for this, it looks fun. Have you thought of adding an image to this post – a hundred square maybe – to make it easy to pin on Pinterest? (I tried but nothing to grab!)

Thanks for the suggestion, Lula. This is an old post, before I learned much about images and blog formatting. I really should go back and add images to several “golden oldies”, I suppose — anyway, I fixed this one.

Yes it did occur to me that this particular golden oldie is 5 years old! I barely knew what blogging was back then! It’s great that you’ve got so many wonderful resources going back so long 🙂

Five years seems like “forever” in internet time. I’m glad people are still finding my posts useful!

I started blogging in 2006, I think (at least, my archives go back that far), and moved to WordPress.com at the end of that year. I transfered posts related to my family with dates intact, but I revised and reposted most of my mathy games and articles over the next year or so. Then, as I learned more about blogging, I went back and added headings and other formatting to make things easier to read. Today I’m adding images to the To-Do list, but it will probably take ages to finish that.

If you find any other posts you’d like to see an image on, just let me know!