Graphical Multiplication

Water Drop

You’ll be amazed at the physics of a simple water drop! This water drop was filmed in ultra-slow-motion at 2000 frames per second, and includes an explanation by a local mathematician (in plain, every English, too!).

Math Recommendations

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 several years across the country and seeing what math options are out there, I searched for more options than what’s traditionally on the exhibit floor.

After talking with math professors from Harvey Mudd, Stanford, Princeton, UCLA, and others, I thought you might like to know about their recommendations for resources that might be useful to you on how to deliver math skills in a way that really lasts.

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How to Square Bigger Numbers Faster in your Head

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 bit of practice) can juggle three balls. Five objects, however, is a whole other story (and WOW factor).

Once you get the hang of squaring two-digit numbers, three-digit numbers aren’t so hard, but you have to keep track as you go along. Don’t get discouraged if you feel a little lost. It’s just like anything you try for the first time… when you’re new at something, in the beginning you aren’t very good at it. But with practice, these steps will become second nature and you’ll be able to impress your friends, relatives, and math teachers.

The video below has two parts:

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How to Add and Multiply Quickly in your Head

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 learn is how to add from LEFT to RIGHT, which is opposite from most math classes out there. I’ll show you how to do this – it’s easy, and essential to working bigger numbers in your head.

Here’s what you do:

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Easy Dice Game for Honing Math Skills

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 in 2nd grade.  (No kidding – when we had ‘math races’, I was always team captain.  Not quite the same thing as captain on the soccer field, though…)

This is one of those quick-yet-satisfying dice games you can play to hone your thinking skills and keep your kids busy until the waiter arrives with your food.  All you need are five or six standard 6-sided dice and two 12-sided dice.  (Note – if you can’t find the 12-sided dice, just skip it for now.  You can easily substitute your brain for the 12-sided dice.  I’ll show you how.)

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Squaring Two-Digit Numbers

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 then square each digit separately, and finally add up the results.

Slightly confused? Great – we made a video that outlines each step. There’s a definite pattern and flow to it. With practice, you will be able to do this one in your head within a very short time. Have fun!
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Multiplying 3-Digit Numbers by 11

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 the extra if needed.

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Multiplying 2-Digit Numbers by 11

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 with such excitement that I couldn’t help it – I started laughing right out loud about how excited everyone was about math… especially on a Saturday night.

When you do this calculation in front of friends or family, it’s more impressive if you hand a calculator out first and let them know that you are ‘testing to see if the calculator is working right’.  Ask for a two digit number and have them check the calculator’s answer against yours.

If you really want to go crazy, you can have math races against the calculator and its operator, just as the Arthur Benjamin video shows.  (Only you don’t need to do the squaring of five-digit numbers in your head!)  Have fun!

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Mental Mathemagic

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 once in awhile paper and pencil, so this area is ‘materials-free’ and jam-packed with great mathematical content. If you’re the parent, stick a calculator in your pocket and test out your kids as they go along.

Some of what we cover here is based on the book “Secrets of Mental Math” by Arthur Benjamin, an incredible professor at Harvey Mudd College. He’s also known as the “Lightning Human Calculator”. Here’s a video about him you may enjoy:

We’re going to break down the steps to really getting to know numbers and put it into a form that both you and your kids can use everyday, including shopping at grocery stores, baking in the kitchen, working on the car, and figuring out your taxes. It’s a useflu tool for flexing your mind as well as appreciating the simplicity of the numerical world.

You can learn this stuff provided you already know how to add and subtract, as well as your multiplication tables. Sound like fun? Then let’s get started! Click here for your first lesson.