Los Angeles Math Circle

LAMC Meetings Archive // Fall 2007 - Spring 2017

For the current schedule, visit the Circle Calendar

Fall 2007 - Spring 2008Fall 2008 - Spring 2009Fall 2009 - Spring 2010Fall 2010 - Spring 2011Fall 2011 - Spring 2012Fall 2012 - Spring 2013Fall 2013 - Spring 2014Fall 2014 - Spring 2015Fall 2015 - Spring 2016Fall 2016 - Spring 2017
8/5/2015
This week, we explored combinatorics, the study of the method of counting. Specifically, we went over the multiplication principle, the addition principle, multiple independent events, permutations and combinations.
Handouts: Combinatorics I | Combinatorics II | Combinatorics (Solutions)
10/4/2015
Working in teams, we will solve a variety of fun problems from a Russian olympiad for middle school students.
Handouts: Handout
Handouts: Handout | Solutions
In our first meeting, we will solve some interesting problems from Moscow Math Olympiads, including problems in geometry, number theory, algebra, and combinatorics.
Handouts: Problem set
We will study Python for the first hour. We will solve problems preparing for AMC8 for the second hour.
Handouts: handout
For our first meeting, we will solve logic problems from a Russian math contest called the Math Festival. These problems require logical reasoning and will help the students exercise their minds.
Handouts: Math Festival | Math Festival Solutions
Welcome to Math Circle! We will be learning about ciphers today and writing some coded messages of our own.
Handouts: Introduction to Ciphers Handout | Introduction to Ciphers Solutions
4PM-6PM In IPAM What makes an election fair?
Handouts: Week 1 Handout
10/11/2015
4PM-6PM in IPAM Is a fair voting system even possible?
During the first hour, we will learn some simplest forms of input and output and examine a very efficient division algorithm. During the second hour, we will be training for the upcoming AMC8 competition.
Handouts: handout
Which polynomials take integer values p(x) at all integer points x? (It's not just the ones that have integer coefficients!) We'll introduce the finite difference operator and apply properties of it to arrive at a simple but surprising characterization of integer-valued polynomials.
Handouts: Handout
We will explore fractions and decimals in depth this quarter. This week, we will prove the relationship between certain fractions and their terminating decimal expansions.
Handouts: Fractions and Decimals 1 | Fractions and Decimals 1 Solutions
The teams formed during the first session will present their solutions to last week's handout to the class. There is no new handout for this week.
Handouts: Handout 1 Solutions
We will continue learning about different types of ciphers and how to use each of them.
Handouts: More Fun With Ciphers Handout | More Fun With Ciphers Solutions
We will learn about infinity by examining Hilbert's Paradox. We will also review some of last week's problems from the Russian Olympiad.
Handouts: Handout02
10/18/2015
This week, we will delve further into fractions and decimals, and prove that every fraction has a repeating decimal expansion.
Handouts: Fractions and Decimals 2 | Fractions and Decimals 2 Solutions
In this meeting we will explore the Stable Marriage Problem, a classical problem in economics initially studied by David Gale and UCLA professor Lloyd Shapley. The pioneering work of Gale and Shapley has inspired hundreds of research articles and several books. We will give a gentle introduction to the Stable Marriage Problem and its applications to college admissions.
Handouts: Handout
We will use recursive functions to draw fractals with the help of the Python's Turtle module. We will further study the properties of the fractals.
Handouts: handout
We will continue to explore infinity with Infinity Rockets in Infinite Space.
Handouts: Handout
We will be working on some practice problems for the Math Kangaroo this week. The Math Kangaroo is an annual mathematics competition that takes place in March. If your child is interested in competing, please register at their website (www.mathkangaroo.org) as soon as possible, as registration fills up quickly.
Handouts: Math Kangaroo Practice Problems | Math Kangaroo Solutions | EE Homework Week 3
Today we will learn about mathematical induction and use it to prove statements involving the natural numbers.
Handouts: Handout | Some Solutions
10/25/2015
We will have a spooky time solving Halloween problems!
Handouts: Halloween Handout | Halloween Handout Solutions | Halloween Homework Solutions
Handouts: Handout for this week and last
This week, we will continue with fractions and decimals and move on to rational and irrational numbers.
Handouts: Fractions and Decimals 3 | Fractions and Decimals 3 Solutions
We will continue our exploration of the stable marriage problem, including variants such as dishonest preference lists, incomplete preference lists, many-to-one matching (the hospital/residents problem), and the stable roommates problem.
Handouts: Handout
For the first hour, Mark Ponomarenko will present his winning project for the last year MathMOvesU competition, Dice, Coin Flips, Quantum Mechanics, and Randomness. We will get back to studying recursive functions and fractals during the second hour.
This week, we will continue to use mathematical induction to prove statements about the natural numbers.
Handouts: Handout
Cryptarithms are mathematical puzzles in which digits are replaced by letters of the alphabet. We will learn to solve some of these.
Handouts: Handout | Solutions
11/1/2015
Handouts: Handout for this week
Today we will solve a variety of problems that have shown up on the AMC 8 math competition over the past thirty years.
This week we will start working on Permutations!
Handouts: Handout | Solutions
We will be working with cubes and their 2D representations.
Handouts: Nets Handout | Nets Solutions | Nets Homework Solutions
Queueing theory applies mathematical models for waiting lines, with applications in the design of telephone systems, computer networks, hospital emergency departments, and more. In a queueing system, customers arrive and are served by servers, and the arrival times of customers and the service times for customers may be random. We study one model of queues (the "M/M/1/K" model) and how customer arrival rate, service rate, and system capacity affect properties of the queue.
Handouts: Handout
We explore the use of modular arithmetic in modern day cryptography. We do this by first exploring the Caesar cipher in the context of modular arithmetic and develop a better cipher called "Simplified RSA".
Handouts: Modular Arithmetic and Ciphers | Modular Arithmetic and Ciphers Solutions
We will continue the study of the fractals from the 10/18 handout.
11/8/2015
We will be continuing our topic with nets today, but this time, with pyramids instead of with cubes.
Handouts: Pyramids and Nets Handout | Homework Solutions
We will figure out the area of Koch snowflake. The area is finite, but the perimeter has infinite length. This way, Koch snowflake provides an example of a curve of infinite lenght bounding a finite area. (Oleg Gleizer)
Handouts: handout
Fair
We will take another look at permutations to continue last week's work.
Handouts: Handout
We continue our study of queueing theory from last week.
Handouts: Handout
We begin our exploration of means by looking at arithmetic means and what they represent.
Handouts: Arithmetic Mean | Arithmetic Mean Solutions
Today, we will learn about the mathematical concept of invariant, and see what a powerful problem solving tool it is.
Handouts: Handout
11/15/2015
"Classical" constructions in geometry in the ancient Greek tradition only allow the use of a straightedge (with no markings on it) and a compass. What constructions can be achieved with different restrictions? In this session, we explore constructions that make use of a marked ruler.
Handouts: Handout
The AMC8 competition takes place on Tuesday, Nov. 17th. Since most of our students participate, we will have a preparation session this time.
We will study Venn Diagrams this week.
Handouts: Handout
We continue our exploration of means by looking at harmonic means and what they represent as well as comparing them to arithmetic means.
Handouts: Arithmetic and Harmonic Means | Arithmetic and Harmonic Means Solutions
Handouts: Splitting the Difference and Problem Solving Handout | Splitting the Difference and Problem Solving Solutions
Today we will work in teams to find invariants and use them to solve problems!
Handouts: Handout | Handout Solutions
11/22/2015
We will study another fractal, called the Sierpinski triangle. If time remains, we will discuss dimensions of fractals.
First proven by Steiner in 1833, every geometric construction with a compass and straightedge can be accomplished using a straightedge alone, as long as a single circle and its center are given. In this session, we will find the constructions that establish the Poncelet-Steiner Theorem.
Handouts: Handout
We will be working on logic problems, as well as word problems.
Handouts: Flipping Triangles | Flipping Triangles Solutions
We finish our exploration of arithmetic and harmonic means and review the concepts we have learned this quarter.
Handouts: Arithmetic and Harmonic Means (Continued) | Arithmetic and Harmonic Means (Continued) Solutions | Quarter Review | Quarter Review Solutions
Handouts: Handout
11/29/2015
Please note that we will not have class on 11/29 due to the Thanksgiving holiday.
12/6/2015
The students, split into pairs, will be competing in proving various mathematical statements, from fractals to geometry to pigeonhole principle. The winner of each pair will progress to the next round. At the end, there will be only one!
This week, we will be playing a game called math dominoes. The students will work in pairs and compete against their classmates, and problems will mostly be based off of what we learned this quarter. In order to facilitate the process, please go over the rules with your child. The domino scoring system could be confusing at first, so please make sure your child knows how the system works prior to class on Sunday.
Handouts: Math Dominoes Rules | Math Dominoes Questions | Math Dominoes Solutions
We will be playing a end-of-quarter review game.
Handouts: Game Questions
1/10/2016
We will use self-similarity to figure out dimensions of various geometric figures from a square, cube, and tesseract to the Koch curve.
Handouts: handout
Welcome back! Math Kangaroo is in a couple of months, so we are doing practice for the competition. Please note that if your child wants to compete, registration is through the Math Kangaroo website, NOT through Math Circle.
Handouts: Math Kangaroo Practice | Math Kangaroo Practice Solutions | Homework #1
Handouts: Cryptography
We will study the Gini index (or Gini coefficient), a statistic commonly used in economics to describe income inequality or wealth inequality.
Handouts: Handout
For the first session of 2016, we will discuss some geometry and go over problems from Math Kangaroo contests.
Handouts: Handout | Solutions
We will study probability in the first half and end the session with the Monty Hall Problem.
Handouts: Handout | Solutions
Today we'll learn tricks for instantly performing calculations in our heads.
Handouts: Handout | Problems 1 | Problems 2 | Problems 3 | Answers
1/17/2016
Today we will be solving problems related to the balance scale.
Handouts: Introduction to Balance Scale | Introduction to Balance Scale Solutions | Advanced Balance Scales | Advanced Balance Scales Solutions | Homework #2
This week, we will discuss shadow geometry and similarity in triangles. We will also practice some hard Math Kangaroo problems.
Handouts: Handout | Solutions
We will define and study a variant of the center of mass of a polygon, called the circumcenter of mass. The circumcenter of mass is defined by triangulating the polygon, finding the circumcenter of each triangle, and taking the weighted average of those circumcenters, where each circumcenter is weighted by the area of its triangle. Analogues of the Archimedes Lemma and the Euler line result.
Handouts: Handout
Handouts: Handout
We will finish our study of fractal dimensions. If time permits, we will begin the new topic, Going Back and Forth between Rational and Decimal Representations of Fractions.
Handouts: handout
Today we will remember what greatest common divisors are from elementary school and learn a powerful way of computing them.
Handouts: Handout | Solutions
We will finish up the Monty Hall Problem discussed last week and move on to Fibonacci numbers.
Handouts: Handout
1/24/2016
Handouts: Handout
Today we will use the division algorithm we learned last week as our main tool in proving that square roots of prime numbers are irrational, that there are infinitely many prime numbers, and that prime factorization of integers is unique.
Handouts: Handout
We will be starting our binary unit by weighing with powers of 2.
Handouts: Binary Part 1 | Binary Part 1 Solutions | Homework #3


We will resume our study of fractions from Problem 8 of the 1/17 handout. We will learn geometric sequences and use them as a tool to find rational representations of real numbers having an infinite recurring part in the decimal form. We will further construct a bijection between the set of rational numbers (p/q, p and q co-prime integers) and the set of real numbers having the terminating (finite) or infinite recurring form.

Handouts: Handout
We introduce the principles of special relativity, Lorentz transformations, spacetime diagrams, and spacetime intervals, and we contrast special relativity with Galilean relativity.
Handouts: Handout
Our main goal for this section is to learn how to determine whether or not a solution exists for the 15 Puzzle. We begin doing this by learning about permutations this week.
Handouts: Handout | Solutions
1/31/2016
We continue our introduction to special relativity, focusing on the spacetime interval, proper time, time dilation, and the twin paradox.
Handouts: Handout


Next time we will resume by discussing Problem 12 from the 1/17 handout at the board. We will proceed to study geometric sequnces, series, and their limits. We will use those as tools for converting real numbers having an infinite recurring decimal part to the rational form.

Handouts: handout
Our main goal for this section is to learn how to determine whether or not a solution exists for the 15 Puzzle. This week, we continue learning about permutations.
Handouts: Handout | Solutions
We will continue our unit of binary numbers.
Handouts: Warm Up | Binary Part 2 | Binary Part 2 Solutions | Homework #4
Handouts: Handout
Today we will explore the concept of a bijection between two sets and see how it can make the notion of "counting" infinite sets rigorous.
Handouts: Handout
2/7/2016
Handouts: Handout
Today we will see that there are actually more than one kinds of infinity. In particular, we will learn that the infinity of real numbers is larger than the infinity of natural numbers.
Handouts: Handout
We will finish our unit on binary numbers.
Handouts: Binary Part 3 | Binary Part 3 Solutions | Homework #5
In the first of two sessions on platonic solids and their symmetries, we give a gentle introduction to the platonic solids and Euler's formula.
Handouts: Handout
We will continue our study of the 1/7 handout. Once finished, we will switch to the new one.
Handouts: Handout

Our main goal for this section is to learn how to determine whether or not a solution exists for the 15 Puzzle. This week, we start tying together and applying what we have learned about permutations and taxicab geometry.





Handouts: Handout | Solutions
2/14/2016
There will be no class this week. See you on the 21st!
Today we will learn how to work with quadratic equations and derive the quadratic formula.
Handouts: Handout
2/21/2016
We investigate the rotational symmetries of the platonic solids. ***For this session, please bring scissors and tape*** for making paper models of the solids. Alternatively, you can make the models at home (see templates below - credit goes to mathsisfun.com) and bring them to the session.
Handouts: Cube and Tetrahedron Model Template | Dodecahedron Model Template | Icosahedron Model Template | Octahedron Model Template | MAIN HANDOUT
We will be working with estimation this week! Please bring rulers to class.
Handouts: Warm Up | Estimation Handout | Estimation Solutions | Homework #6
We will continue our studies of the 1/17 and 1/31 habdouts.
Handouts: Handout
Our main goal for this section is to learn how to determine whether or not a solution exists for the 15 Puzzle. This week, we tie everything together by proving that configurations of the 15 puzzle with opposite parities cannot be solved, and also introduce some logic to show why this is not sufficient.
Handouts: Handout | Solutions
2/28/2016
We will resume the mini-course at Problem 17 of the 1/17 handout.
A homotopy is a continuous deformation with bending, stretching, and squishing, but not tearing or gluing. We introduce the basic ideas of homotopy theory: homotopy equivalence and the fundamental group of a space.
Handouts: Handout
We will be exploring how to break up numbers into parts.
Handouts: Young's Diagrams Handout | Warm Up | Young's Diagrams Solutions | Homework #7
Handouts: Handout
This week, we will discuss prime numbers, Euclid's lemma, the proof of irrationality using Euclid's lemma, and the Goldbach Conjecture.
Handouts: Handout | Solutions
Today we will learn about graphs, prove some of their most important properties, and use them to solve problems.
Handouts: Handout
3/6/2016
This week, we will continue with prime numbers, learning about the existence of infinitely many prime numbers, prime number theory, and twin primes.
Handouts: Handout | Solutions
Today we will continue our study of graph theory and use it to solve real life problems.
We explore applications of complex numbers in plane geometry.
Handouts: Handout
Handouts: Handout (updated)
We will finally finish studying the 1/31 handout. We will solve a few cool problems on geometric sequences and series. In particular, we will resolve the famous Zeno's paradox about Achilles and a tortoise. If time permits, we will start studying the book Algebra by I. Gelfand and A. Shen.
Since the Math Kangaroo competition is very soon (March 17, 2016), we will be doing some more practice today. There is no homework this week -- just finish the handout at home.
Handouts: Math Kangaroo Practice Problems | Solutions
3/13/2016
Handouts: Math Dominoes Rules | Math Dominoes Questions | Math Dominoes Solutions
We will resume studying of the 1/31 handout from Problem 13. We will further use geometric series to resolve the most famous of Zeno's paradoxes, the one about Achilles and a tortoise. If time permits, we will start learning from the Algebra book by Gelfand and Shen.
We will end the quarter with a competition, with teams racing each other to solve the most problems!
Handouts: Problems
We will play a final review tournament.
We finished the remaining packet on prime numbers, and the students took a Math Kangaroo test for practice.
4/3/2016
On our first day back, we will be looking into modular arithmetic. Files will be uploaded the day after the session.
Handouts: Blank copy of worksheet. | Answer key.
We will be using a chessboard today to have some fun with math!
Handouts: Fun on a Chessboard | Fun on a Chessboard Solutions
We introduce game theory and winning strategies, with examples such as Nim and Chomp.
Handouts: Handout
We will see that sometimes it's easier to prove a mathematical statement by showing that it is impossible that the statement is false.
Handouts: Handout
At the beginning of this class we will (hopefully) finish the 1/31 handout, solving Problems 18 - 23. Then we will start a new topic, Mathematical Induction and Peano Axioms. The goal of the new mini-course is to show that a + b = b + a for any two non-negative integers a and b. To prove this seemingly obvious statement, we will need to teach an Artificial Intelligence (AI) some elementary arithmetic, proving that 1 + 1 = 2 as well as associativity and commutativity of addition along the way.
Handouts: handout
For the first meeting of spring quarter, we will take a look at mathematical games and strategies!
Handouts: Handout | Solutions
4/10/2016
We explore games with payoff matrices and mixed strategies.
Handouts: Handout
We will continue studying the 4/3 handout.
We will discuss some applications of math to computer science.
We finish up modular arithmetic this week by moving past simple calculation and onto some interesting applications and characteristics of problems involving modular arithmetic.
Handouts: Blank copy of worksheet. | Answer key.
We will continue our topic on chessboards.
Handouts: Chessboard II | Solutions
This week, we examine how sequences can be defined by the differences between each element. (Pages 1-8)
Handouts: Handout | Solutions
4/17/2016
Two thirds of the class have stopped working around Problem 12 of the 4/3 handout. We will resume at Problem 12 next time. A third of the class has finished the handout. They will be given Olympiad-style problems. 

We will learn about Roman Numerals today!
Handouts: Roman Numerals | Solutions
This session introduces automata theory, a branch of the theory of computation, with deterministic and nondeterministic finite automata and regular languages.
Handouts: Handout (revised)
Today we will learn about the complex numbers and use them to solve problems in geometry and algebra.
We start this week by finishing up the handout from last week. We then start on an introduction to graphs by looking at common problems involving handshaking and graph traversals.
Handouts: Differences (cont'd) | Graph Theory - Handshaking and Chasing Kids | Solutions
4/24/2016
Algorithms (in pseudo-code) and analysis of their time complexity using big-O notation.
Handouts: Handout
We will continue our study of the 4/3 handout. Once finished, we will solve some hard Olympiad-style problems.
We will continue to study complex numbers, and will see how they can be used to solve some geometry problems.
We will be working on solids and their projections today. Please bring cubes (any sort of blocks will work) to class.
Handouts: Projections | Solutions
We continue to study graphs by completing the proofs from last week and also looking at applications of what we have learned about graphs.
Handouts: Handout | Solutions
5/1/2016
This week we talk about strategy of a particular two player game.
Handouts: Blank copy of worksheet.
This week we have a second week of our surprisingly popular "Take Away Games" worksheet! This time around: the game of Nim.
Handouts: Blank copy of worksheet. | Answer key.
We will continue working with projections today. Please bring blocks if you have them.
Handouts: Projections II | Solutions
We will go over the proof of commutativity of addition of non-negative integers one more time. Then we will proceed to solve problems from the next handout. If time permits, we will also discuss the solution of the functional equation xf(x+xy) = xf(x) + f(x^2)f(y). The problem was brought about by Matthew Roth - thanks, Matt!
Handouts: handout
This week, we will finish up our study of graphs by looking at graph isomorphisms and seeing more applications of graph theory.
Handouts: Handout | Solutions
Handouts: Handout
5/8/2016
We continue continued fractions and show that in a certain sense they give the best rational approximations to irrational numbers.
Handouts: Handout
We will get back to studying the Algebra book by Gelfand and Shen.
Handouts: handout
We will be working on our logic today!
Handouts: Island of Knights and Liars | Solutions | Homework
We discuss the exterior angle property in triangles and the angle sum property of polygons.
Handouts: Handout | Solutions
Today we will learn about making and breaking codes!
Handouts: Handout | Solutions
5/15/2016
Handouts: Warm Up Solutions | Perimeter and Area | Perimeter and Area Solutions
We continue discussing angles in a polygon, and then move to several visual proofs for Pythagoras Theorem.
Handouts: Handout | Solutions
Handouts: Handout
Today we will learn what an algorithm is and see why they are useful.
Handouts: Handout
5/22/2016
Today we will be reviewing what we have learned this school year! This is to help with Math Dominoes in the final class, which will cover what we have studied this year. (Please note that not all the concepts are covered in this review for the sake of time.)
Handouts: Handout | Solutions
Handouts: Handout
Handouts: Handout | Solutions
We will continue our study of algorithms from last week.
Today we will finally get to see some applications of complex numbers to geometry!
Handouts: Handout
We will continue studying the Algebra book by Gelfand and Shen based on the 5/15 handout.
5/29/2016
Happy Memorial Day!
6/5/2016
Handouts: Math Dominoes Rules | Math Dominoes Questions | Math Dominoes Answer Key
The re-enrollment test will only cover the topics we went over this quarter: games, successive differences, graph theory, geometry, combinatorics. Attendance is mandatory.
Thanks for your hard work all year! We will close out the year with math relays.
6/6/2016