Archive for Math

How to validate a Canadian SIN number

Posted in Math with tags , , on May 17, 2011 by The Quintessential Geek

Haven’t you ever wanted to know how to make sure a Canadian SIN number is valid?  This could come in handy when doing surprise credit checks on your friends…

1. Write down your sin.  For example: 044-096-857

2. Re-write your sin, but this time, double the 2nd, 4th, 6th, and 8th digits.  Write the number exactly as it appears when doubled, even if it is now a 2-digit number.  For example: 044-096-857 becomes 084-0912-8107.

3. Add up each individual number in the new sequence.  For example: 0+8+4+0+9+1+2+8+1+0+7 = 40.

4. If the sum is a multiple of 10, then the SIN number is valid.  For those mathematically-challenged readers, if the sum ends with a “0”, then the SIN is valid.

Now that you know, go impress your friends.


Young math wiz has fun with doodling

Posted in Math with tags , on January 7, 2011 by The Quintessential Geek

This one will blow your mind:

Binary trees:



Plus, see other videos by user “vihart”.