## Archive for April 15, 2014

### Improving a Math Game

It was 7:02 a.m. on a Saturday morning. Alex ran into my bedroom and woke me from an incredible dream — I was speaking to Riemann, Newton, Pascal, and several other dead mathematicians, and they were just about to reveal an odd perfect number.

“Deedy!” he yelled — somehow *daddy* has been transformed to *deedy* in my house — and I sat bolt upright.

“What?” I asked, rubbing the sleep from my eyes.

“Do you know what 58 × 46 is?”

“I have no idea,” I told him. “What is it?”

“I don’t know, either,” he said. “But it was one of the questions Eli gave me on this morning’s math quiz.”

A few minutes later, he had the answer to that exercise and several others that appeared on the quiz that his brother had created for him.

This is what my twin six-year-olds do. They give each other math quizzes. With two-digit multiplication exercises and slightly more complex combinatorics problems (“How many two-digit numbers don’t have a 3 in them?”). For fun.

So when they recently brought home a math game from school called *One Less* — in which each player rolls a die and has to place a token on a number that is “one less” — my only thought was, “Really?”

Verbatim, here are the directions to the game:

Each player gets 10 counters. Players take turns rolling a die and placing a counter on a number that is one less than the number rolled. The game ends when one player has placed all 10 counters.

Upon reading the directions, I had one question: **RUFKM?**

Let’s review.

- Kids who perform multi-digit multiplication
*for fun*are asked to do single-digit subtraction*for homework*. - The game ends when one player uses all his counters. Mind you, no one actually
*wins*— the game just*ends*.

Well, this will never do.

I opted not to send a note to the teacher about how they need to increase the rigor of their mathematics curriculum. Doing so would just make me **that guy**.

Instead, I decided to turn a bad game into a good game. So we modified the rules as follows:

On a turn, a player rolls a die and places a coin on a space with a value one less than the number rolled. Players alternate turns. A player earns a point each time she gets three of her coins in a row. Game ends when one player has used all 10 coins. The winner is the player with the most points.

This allowed for all kinds of interesting questions:

- What’s the maximum possible score in a game?
- What’s the best arrangement of numbers on the game board?
- Will the first player always win?
- How does the game change if points are awarded for two-in-a-row or four-in-a-row?
- How does the game change if scoring gives 1 point for one-in-a-row, 3 points for two-in-a-row, 6 points for three-in-a-row, 10 points for four-in-a-row, and so on?
- How much wood could a woodchuck chuck if a woodchuck could chuck wood?

We determined the answer to the first question (8 points), and we agreed that we didn’t much care to know the answer to the last question. It seems like the first player shouldn’t always win; but he did in all of the games that we played.

As for the best arrangement of the game board, I have no idea. But if you’d like to explore, several game boards are included in the PDF link below.

What modifications have you made to games to improve them or to make them more mathematically robust?