# Cool Facts

## Happy 09/09/09 day!

For those of you who don’t know, it is indeed 09/09/09 day. Woohoo? Ya I know, it’s just another day, but for some reason the general public LOVES symmetry, so let’s give them what they like to hear ðŸ˜‰ First, since it’s not a leap year, September 9, 2009, is the 252nd day of the …

## On a curious property of 3435

This is a neat little paper regarding the number 3435. Basically it has the following property: 3435 = 3^3 + 4^4 + 3^3 + 5^5 More interesting is that the only other number with this ‘property’ is the number 1. The property is what he calls a “Munchausen Number“. The preprint was written by Daan …

## Why does Canada have skill-testing questions for contests / lotteries?

All winners who are in Canada have to answer math problems before getting any prize. Things like… 90 x 2, then divide by six, then x 12 This question was for claiming an Xbox 360 in a contest, so the answer of course is 360! But WHY?? Americans don’t have to do it, a monkey …

Why does Canada have skill-testing questions for contests / lotteries? Read More »

## How to Compute Cubed Roots Fast

Take a look at this video of Scott Flansburg on the Discovery Channel’s “More Than Human”: In the video you see Scott Flansburg take the cubed root of 658,503 to get an answer of 87 in a matter of a second. How does he do it you ask? This trick does require some memorisation though, …

## How to Guess the Number of M&Ms in a Jar

Adam Micolich has posted a video to show how using the “packing fraction” one can come up with a very accurate guess of the number of M&Ms in a jar.

## How to Turn a Sphere Inside Out Video

This cool youtube video shows how to turn a sphere inside out without making a hole, tearing it, or creasing it!

## Using Fibonacci for mile <--> km conversion

The Fibonacci sequence:1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, …can be used to convert miles to kilometers (and vice versa). For example, to find how many km 5 miles is, take the next Fibonacci number which happens to be 8. Thus, 5 miles is approximately 8 km. Similarly, 8 miles is …

## Prime number trick (with solution)

Using prime numbers, you can amaze your friends with a prime prediction… 1. Ask your friends to pick any prime number greater than 3. 2. Square it. 3. Add 14. 4. Divide by 12. Without knowing which prime number your friends picked, you can still tell them: There will be a remainder of 3. …

## A Theorem About 1 and 0

Well, I don’t know if this is known already, so if it is, please comment the name of the theorem. If it isn’t, then someone put a comment on what it should be called. A number with all of its digits less than 2 (which means only 0 and 1) and has less than 10 …