Mathemagic! Show off your amazing ability to add up big numbers way faster than a calculator. It seems like real ability, from years of practice and study, but there is a secret trick to make it oh-so-easy. People might think you’ve just got all the possibilities memorized, but even that would be an amazing mental feat! There are over 3 million different ways to arrange the pieces.
Setup & Preparation
- This is a single sheet, that gets folded and glued before cutting out the individual pieces. Watch the video for cutting and making details.
Here’s the down-and-dirty explanation: your “key number” is found in the third row of the group of numbers. To find the sum of all of the rows you will put a “2” in front of the digits in the third row, then subtract 2 from the key number. For instance, if the numbers in the third row are 219 (your “key number”), your prediction will be 2,217. (Place a 2 in front, then subtract 2 from the remainder.)
Exception: if your key number ends in 1, you will need to “borrow” from the digit in the tens position. For instance, if the numbers in the third row (your “key number”) are 5,471 your prediction of the sum would be 25,469.
- Perform this virtually or in-person
- Challenge your friends to use their smart phone or calculator to add the numbers faster than you. You will beat them every time!
- You could make a larger set of numbers if you want to perform for a larger audience. Just copy the 12 unique columns of numbers to make a new set. (You don’t need to make all 12, any number of sets will work.)
When I first learned this trick I didn’t understand HOW it works. I was only able to figure it out after manually adding the numbers until I spotted a pattern. This bonus video will give you a better understanding of the math behind the trick.
- Challenge #1: Discover the pattern yourself without watching the video first!
- Challenge #2: Create your own version. Yes, you can! I made one that I call the “11 Code.” In the version of “Instant Math Genius” that you just learned, the prediction is created by adding a 2 in front of the row of numbers in the third column, then subtracting 2 from the digit in the ones column. I dubbed this the “22 Code.” In my “11 Code,” each number stick has three digits. When added together, you will carry a 1, and I chose to subtract 1 from my “key number.”
Let me know what you come up with! Create a video and share it with me or tag me on social media @jeffevansmagic.
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