Curated Video
Maths Tricks Part Two
This video provides three magic maths tricks you can use to practice arithmetic skills or as lesson starters. Examples are given to show how the maths tricks work.
Curated Video
The 50 Cent Riddle That Stumped Australian Students
A 50 cent coin has 12 equal sides. If you place two coins next to each other on a table (see video for diagram), what is the angle formed between the two coins? This was asked to 12th grade (age 17 and 18) students in Australia. Many...
Curated Video
Can You Solve The Code Lock Riddle? A GENIUS Math Shortcut
A safe has a code lock that unlocks if you input the correct four digits, in any order. The lock has a keypad the the digits 0, 1, 2, ..., 9. For example, suppose the unlock code is 1000. The safe will open for any order you input the...
Curated Video
Can You Solve The Chameleon Riddle?
A museum has 13 blue, 15 red, and 17 green chameleons. Whenever two chameleons of different colors meet, they both change into the color of the other chameleon (if blue and red met, for example, they would both turn green). As the...
Curated Video
Multiplying By Lines (Advanced Examples)
Multiplying by lines is a fun way to visually multiply numbers. This is why how you can use it for advanced examples. I wrote about the details in a book: "Multiply Numbers By Drawing Lines" https://www.amazon.com/gp/product/1500866148/...
Curated Video
How To Split A Cake Fairly Using Math
How can 2 people split up a cake, knowing that each person wants to get a larger piece than the other? What about 3 people, or even N people? This is an example of a fair division problem from game theory. There are many cake-cutting...
Curated Video
HARD Geometry Puzzle In The Simpsons
The Simpson's 26th season finale "Mathlete's Feat" is full of mathematical problems. The final problem is a challenging geometric problem. Can you figure it out? You can skip to 4:58 for the solution. Kudos to the writers of The...
Curated Video
Counting To Infinity And Beyond On A Chessboard
The numbers "infinity plus 1" and "infinity squared" sound like they are made up, but mathematicians do use such numbers in set theory. They are called transfinite ordinals and they arise in combinatorial game theory. This video...
Curated Video
Multiply By Lines: Why It Works
This video explains why multiplying by lines works mathematically, starting from basic examples and building up to two digit multiplication. The summary is that multiplying by lines is a shorthand to count hundreds and thousands of dots...
Curated Video
Can You Crack The Code? "Only Geniuses Can Solve"
This puzzle has been shared with dubious claims, but it is still a fun logic problem. Can you figure it out? Examples of puzzle and variants on social media sites https://www.reddit.com/r/puzzles/comments/9aelln/combination_lock_riddle/...
Curated Video
The Friendship Theorem - You Always Have 3 Friends Or 3 Strangers At A Party
In a group of 6 people, you might find that some people are friends on Facebook, or you might find out that no one is friends on Facebook. Show that there is always a group of 3 people in which either: (a) all 3 people are mutual friends...
Curated Video
How Closing Roads Could Speed Up Traffic - The Braess Paradox
The Braess Paradox is an unexpected result from network theory. It states that adding capacity could actually slow down the speed of the network. Applied to highways, the Braess Paradox means the existence of some roads slows down...
Curated Video
Multiply Numbers And Algebra Equations By Drawing Lines
Some people say this is "how the Japanese multiply." Others say this is "Vedic Math." I'm not sure of the origin, but this is a visual way to multiply two numbers and it does work. The video also shows how to use the same method to...
Curated Video
HARD Logic Puzzle - The Seemingly Impossible Counterfeit Coin Problem
An evil warden holds you prisoner, but offers you a chance to earn your freedom. You are given 101 coins, of which 51 are genuine and 50 are counterfeit. Each genuine coin is identical. And each counterfeit coin is identical to a genuine...
Curated Video
Can You Solve The Magical Pond Puzzle?
(Same video with music: https://youtu.be/nF-Gpk0ZpRk) You visit a shrine that has 3 temples. Before each temple, you have to swim in a magical pond. Your path is pond-temple1-pond-temple2-pond-temple 3. Each time you swim, the pond...
Curated Video
Mathematicians SOLVED The BEST Way To Play Memory/Concentration (Card Game)
The card game of memory (aka concentration) is a children's game to test visual recall. Strategically you can figure out the best move by doing probability calculations. This video explains the best possible way to play the game...
Curated Video
111111111x111111111 - Beauty of Mathematics
If you multiply a number with only 1s by itself, you end up with a palindrome of the numbers in ascending and then descending order. People have called this an example of the "beauty of mathematics." If your number has N digits of 1,...
Curated Video
What's The Fewest Wins Needed To Make The NBA Playoffs?
Every year some NBA team seems to make the playoffs with a losing or barely even record. This video considers how extreme the example can go. WATCH how an NFL team with 0 wins could make the playoffs:...
Curated Video
The Wind Chill Formula Explained
The wind chill is a measure of what it "feels like" when the weather is cold. The number is not made up--it's a mathematical formula. This video explains the formula and goes through an example of how to calculate the wind chill. Formula...
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Dark Knight Game Theory (Part 3): Boat Scene Prisoner's Dilemma
The Dark Knight features an example of the prisoner's dilemma. Detailed explanation of this scene http://quantitativepeace.com/blog/2008/07/the-dark-knight.html Video on Prisoner's Dilemma https://www.youtube.com/watch?v=bcUos5ueOhY If...
Curated Video
TOUGH Interview Question - Ways To Give 11 Coins To 3 People
How many ways can you divide 11 coins to 3 people? How many ways are there if each person has to get at least 1 coin? This puzzle is an example of a technical interview question. The video demonstrates the solution, which indicates the...
Curated Video
This Problem Stumped Vietnamese Students - Solution To Viral Puzzler
This problem was asked to 3rd graders (8 year olds) in Vietnam. Can you figure it out? Place the numbers 1 to 9, using each number once, to make a valid equation. In this video I explain how you can solve this problem logically. UPDATE:...
Curated OER
What's an Example of a Word Problem That Has a System of Linear Equations with Infinite Solutions?
How can a math problem have an infinite number of solutions? No way! There has to be just one answer. Follow along as the instructor walks you through this explanation and shows you how a math problem can have an infinite number of...