## Sunday, September 4, 2022

### polyGONE

Some years I'm fortunate to be able to lead a capstone seminar where future teachers research math games and develop a math game of their own.

Melanie Hanko came into seminar with a vision of making a math game inspired by Bohnanza, a collecting and trading game with a lot of strategy and a fair amount of luck. She really worked on the details for this game. Often times we focus on making games that use minimal materials, but this is much like a commercial game, with a lot of necessary components. For a teacher wanting to give it a try, I would love to see the learners get involved with making the cards.

Melanie writes:

In the hopes of making an exceptional game, I set off looking for game structures that were simple but had a lot of potential. Then, interested in the structure of Bohnanza: The Bean Game, I started looking at mathematical content that involved some sort of sorting. Eventually, I landed with organizing shapes into hierarchies - specifically quadrilaterals. This is largely based on a 5th grade standard. polyGONE: The Shape Game is the sort of game that engages students with mathematical discourse and reasoning minus the negative attitudes about math. While players need to have a good base understanding of the hierarchy of quadrilaterals and the different types of triangles, this game will help players to create more connections between shapes and gain a broader understanding of what gives a shape its name.

A lot of the pieces of the game are designed with specific purposes, either to clear up misunderstandings or confusion in early versions or to clear out some of the underlying confusion. The part of the game with the most meaningful design, is the deck of cards. These cards are created to broaden player’s understanding of shapes. Included in the cards are traditional and non-traditional shapes. Different cards show different attributes of a family, like parallel lines, congruent lines or angles, and even lines of symmetry. Different cards show different looking shapes - for example both a concave and a convex kite. This differentiation within the cards, will broaden player’s understanding of shapes and relationships between shape families.

Another purpose of the design of the cards is to increase their usefulness. With all of the cutting and printing, the cards better be usable for multiple occasions. Since there is so much differentiation between the cards, you can easily use them in a sorting or a matching activity. Even before playing the polyGONE, you could match cards based on if they have certain attributes. For example, matching cards that have two pairs of congruent sides. The cards can be used in explorations of the “rules” for each shape family. For example, deciding if a right angle is necessary for a trapezoid, or if it is something that only occurs in some trapezoids. These and other activities can be easily supported with these cards and will help to broaden students’ understanding of shapes and the shape hierarchy.

The teachers also make a video for a good math game which they would like to promote. Melanie found one of Kent Haines' games that is a very good Nim variant. She writes:

The 100 Game is a part of the math game genre of nim, which are mathematical strategy games in which players take turns removing objects from distinct piles or groups. Not only does the 100 Game require almost no materials and setup, but it is a fun game full of mathematical reasoning. In the forefront, the game makes practice subtracting within 100 enjoyable. Behind this practice, players strategize how to not be the last person to take away from the total. This requires deductive reasoning, an important mathematical skill. Besides the math, this game is quick to learn and engages players quickly - even unwilling players.

Mathematical Applications: practice subtraction, strategy and deductive reasoning

Materials: paper and pencil, two players

Object of the Game: Players start at 100 and subtract any number 1-10 from the total. The goal is to NOT be the last person to subtract a number. So you want to subtract the second to last number from the total.

How to Play:

• Player one will start the game by saying “100 minus [blank] equals [insert new total]. You can only subtract numbers from 1-10.
• Then both players will write out the subtraction sentence player one just said out loud.
• Now, it’s player two’s turn. This player will pick a new number to subtract, say the subtraction sentence, and both players will write down the sentence.

Example Play: Here is an example of what each player would say for a few turns. Remember that BOTH players are writing down the subtraction sentences as well.

• Player One (P1): “100 minus 5 equals 95”
• Player Two (P2): “95 minus 10 equals 85”
• P1: “85 minus 7 equals 78”
• P2: :78 minus 9 equals 69”
• ...
• P2: “23 minus 9 equals 14”
• P1: “14 minus 3 equals 11”
• P2: “11 minus 10 equals 1”
• P1: “1 minus 1 equals 0”

In this game, player one lost because they were the last person to subtract a number from 100.

Notes: After you play this game a few times, you might start to develop a sure strategy. In fact there is something special about the number 12. Finding this strategy is what engages players in deductive reasoning. Some questions you might want to ask yourself or your students/children include the following:

• What should your strategy be?
• How can you ensure that you will win?
• At what point in the game do you need to start using your strategy?
• Does it matter who goes first?

Be sure to check Kent's blogpost for more ideas.