# Activities Database

# Activities Database

### 5 Squares Problem

How many different shapes can you make by joining four squares along whole edges? How about 5 squares?

### Bubbling Cauldrons

We will place numbers, starting from the number 1, into our cauldrons. No two numbers in a cauldron can add to another number in the same cauldron. What is the largest number you can place into the two cauldrons without exploding?

### Contextualizing Mathematics: Fortnite – Surviving the Storm

In this session, developed as part of the Math Circles of Inquiry project, you are playing Fortnite. There are three loot boxes marked by your teammates. Which one is the best to go to? In other words, which point is closest to a given point outside a circle, the center of the circle or one of two points of tangency connecting the outside point to the circle? The highly contextualized nature of the problem posed will make the mathematics more appealing for students to explore. Moving between individual work, partner work, and whole class discussion, students make their predictions and...

### Conway’s Rational Tangles

What do adding positive and negative fractions have to do with tying knots? In this entertaining lesson, students will use ropes to explore and identify mathematical operations that untangle knots and lead to new thinking. Simple operations of twists and rotations circle back to practicing the addition of positive and negative fractions.

### Digit Sums

In these puzzles, there are circles with numbers and empty circles. The goal is to put whole numbers in empty circles so that each circle has the sum of the digits of numbers connected to it. This is done by adding all the digits you see of each number (the digits of 18 are 1 and 8).

### Don’t Say 13

The rules to this game are simple -just Don’t Say 13… That should be easy right? This activity will explore a classic math problem, give students an idea of how to strategize, and learn about modular arithmetic.

### Frogs and Toads

Frogs can only move right, or down, and toads can only move left, or up. Can you exchange all the frogs and toads? Can you create a formula for the fewest number of moves? This deceptively simple puzzle starts with a row of frogs and toads, then advances to a grid. The game can be played with manipulatives, online, or even with people to provide an engaging, solitary or cooperative activity for all ages.

### Function, Function, What’s Your Model?

Developed as part of the Math Circles of Inquiry project, this session is an introduction to functions. This module allows students to investigate the definition of a function, function notation, key features of a function including increasing, decreasing (in both interval and inequality notation), maximum and minimum, average rate of change and domain and range.

Materials include a full packet of worksheets pertaining to this unit (54 pages). This part of the unit (not including transforming functions) should take about six hours of class time.

### Gerrymandering

Merriam Webster defines gerrymandering as “the practice of dividing or arranging a territorial unit into election districts in a way that gives one political party an unfair advantage in elections.” This activity tries to make sense of that definition using a few examples.

### Humans, Zombies, & Other Problems Crossing the River

A town has recently been plagued by an epidemic of zombies! Luckily, the virus has just started to spread and the infected are able to stave off their hunger for human brains… for now. In fact, they’re willing to work alongside the remaining humans to help them get across a river to safety. Can you get all the humans and zombies across safely?

### I Walk the Line

Your regular commute begins at your house and ends at your office at the corner of 5th street and 6th avenue. You have been making this trip for years, but you are the restless (or adventurous) type, and you try to take a different route each day. At some point, you start to wonder how long it will take you to try all of the routes.

Oh, did I mention that you have to avoid the zombies?

### Investigating the Surface Area of Prisms

Developed as part of the Math Circles of Inquiry project, this module enables students to build understanding about surface area. Students will complete three tasks dealing with surface area and volume of rectangular and triangular prisms, including a real world investigation, presented in Three Acts. The tasks will go from the concrete to the abstract as students gain understanding of what it really means to calculate surface area and volume. The module includes a refresher on area and perimeter.

### Magic Squares

Your goal is the place the numbers 1 – 9 in a 3 by 3 grid so each row, column, and diagonal add up to the same magic number. Can you find what this magic number is?

### Measuring Up: “Perfect” Rulers

Is it possible to measure all possible integer lengths on a ruler without marking every integer on that ruler? This is an engaging and challenging problem for all. Beautiful mathematics can be revealed while delving deeper into this seemingly easy question.

### Monty Hall Problem

A prize is hidden behind one of three doors. You choose the door where you think the prize is hidden. But before the door is opened, one of the other 2 remaining doors is opened to reveal no prize. You can choose to keep the door you chose earlier or switch to the other remaining door. What should you do?

### One-Player Games

Here is a collection of seven one player games, and one two player game. Your goal in each game is to find the winning strategy. As the rules change, can you still win? Various mathematical strategies can be employed, including working backwards, problem posing, invariants, and parity. Each game can be explored alone or in sets, providing material for several circle sessions or the classroom.

### Practical Probability: Casino Odds and Sucker Bets

Gambling casinos are there to make money, so in almost every instance, the games you can bet on will, in the long run, make money for the casino. However, to make people gamble, it is to the casino’s advantage to make the bets appear to be “fair bets,” or even advantageous to the gambler. Similarly, “sucker bets” are propositions that look advantageous to one person but are really biased in favor of the other. In this article, we’ll examine what is meant by a fair or biased bet, and we will look in detail at some casino games and sucker...

### Prejudiced Polygons

Triangles and Squares live together in neighborhoods. However, the Polygons all believe two things: “I am unhappy if fewer than 1/3 of my immediate neighbors are like me.” and “I am unhappy if I have no immediate neighbors.”

### Puppies & Kittens

A local animal shelter has a puppies and kittens available for adoption that you just happen to be itching to own! In this week’s “paw-some” activity, two players begin with a certain number of animals to choose from and take turns adopting animals. The player to adopt the last animal wins! We’ll be constructing a strategy for beating this game and exploring a bit of sequences.

### Queen’s Move

Students will explore a game between two players moving a chess Queen from place to place on a square grid. The Queen may move any number of spaces to the left, any number of spaces downward, and any number of spaces on the downward-left pointing diagonal. Each player takes turns using these moves. Whoever gets the Queen to the bottom-left square first wins!

### Skyscrapers

Skyscrapers come in so many different sizes! Sometimes you can’t see small skyscrapers if tall ones are in front of them. Using clues about how many skyscrapers you can see from each side you look at them, can you figure out the layout of the entire city?

### Supreme Court Handshakes

Developed as part of the Math Circles of Inquiry project, this session is a good introduction to the 8th grade or Algebra Math curriculum using inquiry based instruction. Students are asked to use their problem solving skills in order to determine the relationship between the number of Supreme Court justices and handshakes that occur when each pair shakes hands exactly once. Students will begin exploring with simpler numbers and work up to creating an algebraic expression to represent the function. This lesson allows for multiple representations by using a table, list, circle diagram, matrix and manipulatives.

### The Game of SET

SET is a fun game that can be enjoyed by kids as young as 6 and is challenging even for adults. It is rich in counting problems and is great for getting people to pose problems. It is also an example of a finite geometry and interesting to explore how well one’s geometric intuition works.

### The Jug Band

“Using just that 5 pint jug and that there 12 pint jug, measure me 1 pint of water!” Is this possible with just the two jugs? What about a 7 pint jug and 17 pint jug? Or p pint and q pint jugs?

### Tic-Tac-Toe 2.0: New Takes on an Old Classic

The game of Tic-Tac-Toe has roots going back centuries. Grid-style game boards have been found in Ancient Egypt, during the Roman Empire, and in our current age on restaurant placemats. Multiple avenues of exploration are possible with this simple children’s game. A related game called “Gobblet Gobblers” takes Tic-Tac-Toe to a whole new level!

### Winning the Lottery, An Expected Value Mystery

In 2005, while researching the expected value for lottery tickets in various states, a group of MIT students won millions of dollars in the Massachusetts $2 Cash Winfall drawing. Do you want to know how they did it? This teacher led activity starts with a lottery, explores expected value, and finally ties into finite projective geometries.