Math Circle Activity Database

Activity Authors
Activity Circles
Click To Sort By
  • 1st - 2nd (5)
  • 3rd - 5th (14)
  • 6th - 8th (23)
  • 9th - 12th (20)
  • College Level (13)
  • For Teachers (13)
  • Probability and Statistics (1)
  • Algebra / Arithmetic (10)
  • Combinatorics (13)
  • Geometry (11)
  • Mathematical Games (6)
  • Mathematical Modeling (7)
  • Number Theory (5)
  • Problem Solving / General (14)
Supporting Materials
Supporting Materials
  • Facilitator Guides (22)
  • Handouts (12)
  • Lesson Plan (3)
  • Photos & Videos (19)
  • References (14)
  • Virtual Tools (8)
Session Styles
Session Styles
  • Work Backwards (5)
  • Integrates Technology (7)
  • Kinesthetic Element (3)
  • Manipulatives (14)
  • Multiple Representations (6)
  • Problem Posing (11)
  • Problem Sets (13)
  • Try a Smaller Problem (10)
Mathematical Practices
Mathematical Practices
  • MP1 - Make sense of problems and persevere in solving them. (22)
  • MP2 - Reason abstractly and quantitatively. (11)
  • MP3 - Construct viable arguments and critique others' reasoning. (13)
  • MP4 - Model with mathematics. (13)
  • MP5 - Use appropriate tools strategically. (8)
  • MP6 - Attend to precision. (7)
  • MP7 - Look for and make use of structure. (17)
  • MP8 - Look for and express regularity in repeated reasoning. (13)

Bubbling Cauldrons


Place our numbers into the cauldrons in ascending order – you can choose which cauldron each one goes in. However, if two numbers in one cauldron add up to a third number in that same cauldron, they bubble up and cause an explosion! This means that all the numbers, leave the cauldrons, and you must start all over again.

Our goal is to find the largest number we can place in our cauldrons without them exploding… do you think you’re up for this daunting task?

Factor Game


A teacher challenges students to a game. The rules are explained as the game progresses. The player with the highest total wins! Students then play against each other. Afterwards, while analyzing the game, prime, composite, perfect, deficient, and abundant numbers are discovered and defined. Students again play the game using the strategies they determined.

In a professional development video, teachers focus on the topic of number systems and number theory using a game setting to investigate the properties of prime, composite, abundant, deficient, and perfect numbers. This video can be used in conjunction with The Factor Game lesson plan.

Flipping Pancakes


The Pancake Problem, first posed in 1975, is a sorting problem with connections to computer science and DNA rearrangements, which leads to discussions of algorithms, sequences, and the usefulness of approximations and bounds.

The original problem was first posed by mathematician Jacob Goodman under the pen name “Harry Dweighter” (read it quickly) in 1975, and it has delighted math enthusiasts (including undergraduate Bill Gates) ever since!

Folding Perfect Thirds


Imagine you’re packing for a trip, and you’re planning on bringing your favorite tie. It’s too long to fit in your suitcase, even after folding it in half. You would fold it into fourths, but you don’t want all of those creases ruining your tie. You’ve decided folding it into thirds will be the perfect length to fit in your suitcase without noticeable creases on your tie. However, you don’t have a ruler or any means of making sure your tie is folded into perfect thirds. Is there anything you can do about this?

Grid Power


“When I grew up in the Soviet Union, all we used for math was grid paper. Grid paper leads to discovery.” This is how Tatiana Shubin, San Jose State University, begins her lesson demonstrating the myriad of wonderful math questions arising from a simple sheet of grid paper. Attempting to count all squares of any size on a limited grid will require participants to persevere, organize their thinking and construct viable arguments.

Humans, Zombies, & Other Problems Crossing the River


A town faces 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?

Mind Reading With Math


For the Math Mind Reading Trick, you’ll need a volunteer who’s willing to have their mind read. The person performing the trick holds out the four cards and askes their volunteer to pick a number (whole numbers only, no fractions allowed!) between 1 and 15 and keep it a secret. Next, the mind-reader asks the volunteer if their number is on the cards one-by-one. The volunteer answers the questions with yes or no answers, and with some magic and a little math, the mind-reader figures out their number!

Mondrian Art Puzzles


You’re Mondrian’s mathematical boss. Instead of allowing Mondrian to randomly draw rectangles and colors -you lay out requirements: 1) Mondrian must cover an N by N canvas entirely with rectangles. 2) Every rectangle in the painting must have different dimensions. 3) Mondrian must use as few colors as possible, and rectangles with the same color cannot touch one another.

Under these rules, Mondrian must try to minimize his score. A painting’s score is the area of its largest rectangle minus the area of its smallest rectangle.

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. We’ll examine what is meant by a fair or biased bet and look in detail at some casino games and sucker bets. Various problems can be...

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!

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 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?

Scroll to Top