Cryptography is the writing and decoding of secret messages, called ciphers. Now for governments these secret ciphers are a matter of national security. They hire special cryptanalysts who work on these ciphers using cryptanalysis. The secret is, solving substitution ciphers…
This is not only a neat trick but a very practical skill – you can figure out the day of the week of anyone’s birthday. If you were born in the 20th Century, (1900-1999), we can use math to find…
Can you look at a number and tell right away if it’s divisible by another number? Well, it’s pretty easy for 2 – if it’s an even number, it’s definitely divisible by two. Testing whether a number is divisible by…
Remembering and visualizing most shapes is pretty easy, right? An octagon can be a challenge for some (it has eight sides, while the commonly-confused hexagon has six sides). In this experiment, we try to recall and draw some everyday objects…
This is a cool two-player geometry game with lots of strategy involved. You’ll need paper and two different colored markers or crayons. The object is not to draw a triangle (or to force your opponent to draw one). Take a…
If a friend had chose a three-letter word and asked you to guess it, how would you start? It seems like it might take a while to narrow it down, right? This is a neat word guessing game that uses…
This is one of my family’s favorites! It’s a guessing game, but you can use logic and strategy in order to guess the numbers very quickly. In this video, I’ll show you in more detail how it works. I’ll also…
Magic squares have been traced through history as known to Chinese mathematicians, Arab mathematicians, India and Egypt cultures. The first magic squares Magic squares have fascinated people for centuries, and historians have found them engraved in stone or metal and…
Hex is a super fun game! It starts with a grid of hexagons (six-sided shapes) and two players. You can color in any cell on your turn. The ultimate goal is to be the first one to complete a chain…
This is a neat logic trick which allows you to flip over a stack of cards numbered 1-10. When you flip the back upright, they are in numerical order. There is a special way to make it work, so pay…
This is a really fun riddle! It’s a math logic puzzle involving the calendar that will really blow your mind. Pay close attention to the clues I give in the video and see if you can work out how it…
For this puzzle, you’ll use three cups and eleven objects. The first challenge is to put an odd number of objects in each cup. Is this pretty simple? How many different combinations can you come up with for the eleven…
The Date Shift cipher is a much harder code to break than, for example, the more simple Shift cipher. This is because the shift number varies from letter to letter, and also because it’s polyalphabetic (this means that a single…
Shift ciphers were used by Julius Caesar in Roman times. A key is a number that tells you how many letters you’ll shift in the alphabet. These are fairly simple to encode and decode. However, you have to be extra…
In this video, I demonstrate a Twisted Path Cipher. It uses a matrix and a path in order to encode your message. The shape of the path you create within the matrix of a Twisted Path Cipher determines how difficult…
In math, probability is how likely it is that something will occur (or not). Probability is expressed from a range from 0 to 1. A probability of zero means that a thing will definitely not happen – it’s impossible. But…
Imagine that you are on a game show with a chance to win a car. There are three doors and the car is behind one of them. You just have to choose the correct door! You can use probability to…
If I said “3!“, would you think the 3 is really excited, or that you have to shout the number? In fact, it’s a mathematical operation called factorials, and boy are they fun! They may seem complicated at first, but…
Here’s an interesting math puzzle. If you’re at a concert that’s also being broadcast live on the radio, who will hear the music first? Will it be you, or people listening on the radio? In this video, I’ll show you…
Have you ever heard someone refer to a “million billion” of something? Is that more or less than a “billion million?” In this video, I’ll show you how to write down these numbers and figure out which one is larger.…
Numbers really can be huge – some are too big to even imagine! Have you ever seen a million pieces of candy? Or have you ever even tried to count to one million? In this video, we’ll try to figure…
In this video I’ll show you how to use a actual cipher machine called a scytale. This was first used in ancient Greek and Roman times, most notably by the Spartans. To make a scytale, use a cylinder with a…
Code machines – or cipher machines – can be used to encode and decode messages. One everyday example of a code machine that you can easily access is a telephone. Watch this video and I’ll show you how it works.…
This is a super hard cipher to break. It’s encoded by taking pairs of letters and numbers from a matrix. There are three rules to follow. If both letters are in the same row, then use the letters immediately to…
Cryptograms are solved by making good guesses and testing them to see if the results make sense. Through a process of trial and error, you can usually figure out the answer. Knowing some facts about the English language can help…
Polybius was an ancient Greek who first figured out a way to substitute different two-digit numbers for each letter. In the Polybius cipher, we’ll use a 5×5 square grid with the columns and rows numbered. Take a look at the…
The Pig Pen cipher is of the most historically popular ciphers. It was used by Freemasons a century ago and also by Confederate soldiers during the Civil War. Since it’s so popular, it’s not a very good choice for top…
Everyone old enough to remember the Rubik’s Cube craze of the 1980s in the USA also remembers how it was near impossible to solve the thing! Originally created by a professor of architecture Erno Rubik, it was sold to a…
Kaleidocycles are a three-dimensional paper sculpture you can turn around and round! Flexagons were first created by Arthur Stone at Princeton University in 1939, which were later published in 1959 to the general public in Scientific American. These are simple to make…
This isn’t something you’d normally find in a math class, but I find it incredibly useful to know how to turn a simple sheet of paper into the envelope you can mail it in. The letter you write goes on…
If you’ve ever wanted to sneak a peek into my cabinet of educational games and books for kids, now is your chance. Use this list for gift ideas, boredom busters, and just plain family fun. Some of these games you…
Ever wonder what sines, cosines and tangents are used for in the real world? The truth is, most kids and teachers that study this stuff DON’T actually understand what it’s useful for! So let’s take a sneak peek at a…
Sadly, most kids get scared off too soon with math courses that don’t make a lot of sense. For the kids who do make it to calculus, this is the class that will finally finish them off without hesitation, and…
One day, my kid asked me how a calculator comes up with its answers. That’s a great question, I thought. How does a calculator do math? After thinking about it, I realized this was a great way to teach him…
Did you know I carry a set of dice in my pocket just for this game? It’s as old as the hills and just as fun to play now as it was when I was a little math whiz back…
This neat little trick shortcuts the multiplication process by breaking it into easy chunks that your brain can handle. The first thing you need to do is multiply the digits together, then double that result and add a zero, and…
If you can multiply 11 by any 2-digit number, then you can easily do any three digit number. There’s just an extra step, and make sure you always start adding near the ones so you can see where to carry…
We’re going to throw in a few math lessons here and there, so if math really isn’t your thing, free free to just watch the videos and see what you think. All of these lessons require only a brain, and…
Here’s our first MATH lesson. It is so easy that one night, I wound up showing it to everyone in the pizza restaurant. Well, everyone who would listen, anyway. We were scribbling down the answers right on the pizza boxes…
This is a really neat game invented in 1967 by two mathematicians that was soon after published in Scientific American, where it caught fire with people all over the world. It’s a very simple game with a lot of interesting…
Having trouble with your 6, 7, 8, and 9 multiplication tables? Sneak a peek at this nifty trick for multiplying single digits together. All you need is a set of hands and about ten minutes, and you’ll be a whiz…
Cryptarithms are a puzzle where the digits are replaced by letters or symbols. When the numbers are replaced by letters of the alphabet and it spells something readable, it’s called Alphametics. Download the student worksheet that goes with this lesson.…
Want a peek under the ‘hood’ of my brain when I do a mental math calculation? This video is a slow-motion, step-by-step snapshot of what goes on when I add numbers in my head. The first thing you need to…
On March 14 at 1:59pm, folks from all over the world celebrate “Pi Day” with games, activities, and pie-eating contests. Here are my best resources for showing kids how pi shows up in the real world and also how to…
When it’s too hard to count ’em up and too much time to calculate, it’s time to guesstimate the answer. I use this technique all the time to “ball park” my answer so I know if I’ve made a mistake…
If you hate long division like I do, then this lesson will be very useful in showing you how to make the most out of your division tasks without losing sleep over it. It’s easy, quick, and a whole lot…
If you don’t have the patience to do multiplication on paper for every single math problem that comes your way, then you’ll really enjoy this math lesson! You’ll be able to multiply one and two digit numbers in your head,…
In school, you are trained to solve math problems on paper, at a desk. The problem with that is, for most people, math problems don’t usually come with a desk or a pencil. They pop up in the checkout line…
If you haven’t memorized your multiplication table yet, I am going to show you how to you need to memorize only three of the 400 numbers on a 20 times table in order to know your table. Download the student…
Launching rockets requires a lot complicated math, but it all starts with Newton’s Laws of Motion. We’re going to get a taste of the math behind the real rocket science. Using math with rocket science experiments allow scientists to figure…
This math lesson is so easy that one night, I wound up showing it to everyone in the pizza restaurant. Well, everyone who would listen, anyway. We were scribbling down the answers right on the pizza boxes with such excitement…
Squaring three-digit numbers is one of the most impressive mental math calculations, and it doesn’t take a whole lot of effort after you’ve mastered two-digits. It’s like the difference between juggling three balls and five balls. Most folks (with a…
Most resources that public school advisers suggest for gifted or bright kids are a ‘mile wide and an inch deep’ – they don’t really go into depth on any one area. After traveling to dozens of home school conventions for…
The trick looks impressive, so be prepared for jaw-drops when you show this to kids and adults. But can you figure out how it works? I’ll give you a hint: think about how to represent placeholders of powers of 10……
A pantograph, first invented in the early 1600s, was used to make exact copies before there were any Xerox machines around. It’s a simple mechanical device made up of four bars linked together in a parallelogram shape. Here’s how it…
Fractals are new on the mathematics scene, however they are in your life everyday. Cell phones use fractal antennas, doctors study fractal-based blood flow diagrams to search for cancerous cells, biologists use fractal theory to determine how much carbon dioxide…
If only you could keep better track of big numbers, adding and multiplying your head wouldn’t be such a problem! But fear not… I have a trick that might be just the ticket for your brain! Use this secret phonetic…
Once in awhile, mathematicians come up against something that really seems impossible on the surface. These seemingly “impossibilities” not only cause them to sit up and take notice, but often to create new rules about the way math works, or…
This is a neat trick that you can use to really puzzle your friends and family. If someone gives you a three-digit number, you can actually figure out what the end result will be after you’ve received two additional numbers,…
Have you ever heard of a dollar word search? It’s a special kind of puzzle where the letters in a word add up to a coin value. For example, an A is worth a penny, the letter B is worth two…
Do you think you’ll need to know how to multiply by 12 or 11 more? Think of it this way: how often do you need to figure out how many dozen you need of something? It comes up a lot…
What is math? It can be compared to a very useful tool, or maybe a collection of tools. Sometimes textbooks concentrate a lot on teaching about the small details of each and every type of tool. But it’s also really…
Did you know that you can step through a sheet of paper using just a pair of scissors to help? Does this sound impossible? Well, this is where math and magic come together! Watch the video and I’ll explain. NOTE:…
Although the Möbius strip is named for German mathematician August Möbius, it was co-discovered independently by Johann Benedict Listing, a completely different German mathematician, but at around the same time in 1858. Weird, right? But that’s not the only strange…
There’s more than one way to fold a cube. So print out the attachment, grab some tape and sticky notes and we’ll have some fun with geometry! How many different shapes can you use to make a cube? NOTE: You’ll…
The first folks to play this game lived in the Roman Empire, but it was called Terni Lapilli and instead of having any number of pieces (X or O), each player only had three, so they had to move them…