How to: organize your digital library of papers

There are a few ways you can organize the digital papers you download.

1. One such way is using Zotero. Basically, Zotero [zoh-TAIR-oh] is a free, easy-to-use Firefox extension to help you collect, manage, and cite your research sources.

2. Another one is to use Mendeley.
In addition to being multi-platform, it also has
a web site where you can sync your PDFs for online access. It also extracts the metadata from your PDFs (like title,
authors, journal titles) and fills in many fields for you. You also have PDF renaming options.

3. Finally, a lot of people use papers:

I haven’t tried any of these though, so I wouldn’t know which one to recommend. I personally just organize the PDF’s by fields of research and name each one as the title of the paper. It helps having hard copies as well 😀

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Solving cryptograms in 10 simple steps


Can you decode it? If not, let’s go through some general strategies that will help 😀
1. Words with one letter are either “A” or “I”.

2. A very frequent 3-letter word is “THE”.

3. There is an apostrophe then the letter after it is T or S. (DON’T, CAN’T, CAT’S, etc).

4. If it ends in a question mark, the first word is usually:


5. Frequent pairs of constants are TH, WH, SH or CH.

6. Frequent word endings are:

“TION”, “ENT”, “ANT”, “ING” “ERS”, “ENS” and “ED”.

7. Short words where “ING” or “ED” are at the end sometimes have a double up on the last consonant, like “HOPPED” and “HUGGING”.

8. In 2 letter words one is a vowel (or Y). Example, IF, BY, HE, AT.

9. If it’s a word like [] ‘ [] …. then the second one is usually a D (or could be an M). Example, I’M or I’D.

10. Guess and test!!

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Eyeball math game

Apparently I’m pretty bad at using my eyes. You can try out this game at
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Divisibility Tricks

Is the number N divisible by…. 2? 3? 5?

Everyone knows the first trick:
N is divisible by 2 if its last digit is 0, 2, 4, 6, or 8 (that is, last digit is even).

Most people know the next trick:
N is divisible by 3 if the sum of the digits is also divisible by 3.
You can repeat this rule too.

For example: Is the number 93,225 is divisible by 3? Well…

9+3+2+2+5 = 21

And, 21 is divisible by 3, hence 93,225 is divisible by 3.
N is divisible by 4 if the last two digist form a number divisible by 4.
do an example: Is the number 23894723985729316 divisible by 4? Well the
last two digits is 16 and 16 is divisible by 4, so YES!

N is divisible by 5 if it ends in 0 or 5.

For 6, we just combine the rules for 2 and 3:
N is divisible by 6 if it is divisible by both 2 and 3.

For the rest, we will stick with prime divisors p.
Consider multiples M of p until:

M*p+1=0 (mod 10)

We want the smallest such M.

n = (Mp+1)/10

Consider n and p-n, and usually we just pick the lowest.

to find out if a number is divisible by p, take the last digit of the
number, multiply it by n, and add it to the rest of the number (OR:
multiply it by (p – n) and subtract it from the rest of the number).

If you get an answer divisible by p (note that this includes 0), then
the original number is divisible by p. Repeat the rule if you don’t
know the new number’s divisibility.

Now try to see if you can come up with the rule for 7! One thing you might find interesting is the following post that discusses using a ‘divisibility graph‘ for 7.

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Silly exam answers

More funny exam answers…

This one is silly, gotta love teachers!!
teacher fail at math letter
police roadblock in the way drawn on test exam

Common mistakes, uncommon picture…
adorable panda drawn on test exam

Rainbows!! and a bunny!
adorable bunny and rainbow drawn on test exam

paint my house question on test exam fail

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First Annual Special Mathlympics to be hosted by Canada in 2012

What is it?
Special Mathlympics is an annual event with the main goal of stimulating interest and igniting passion in mathematics!

Who can participate?
The competition is open to people of all ages who are special (in the sense that they are mathematically challenged).

When/where is it?
On March 14th, 2010, the very first Special Mathlympics will take place in Toronto, Ontario. The Special Mathlympics occur every year! The host city for 2011 will be Paris, France.

Schedule of events:
Day 1: Addition
Day 2: Subtraction
Day 3: Multiplication
Day 4: Puzzles

On day 4, teams will answer tough mathematical puzzles like the famous Moomahata bird problem:

  • Suppose Moomahata has 3 birds and Meemahata has 2 birds. One the birds that Meemahata has is named Moomahata and the other is named Meemahata. The birds that Moomahata have are named: Meemahata, Moomahata, Meomahata. Suppose that Moomahata has $7 per bird and the bird named Moomahata has $2 per Meemahata. If Meemahata has $3 per bird and an additional $1 per Meemahata, then how much money does the bird Meemahata that is owned by Moomahata have?

Register your team TODAY for the chance to win the world title!

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How to solve the sudokube

The Sudoku Cube is a ripoff of the Rubik’s Cube, where each face has the numbers 1-9 instead of colours. The goal:

put the numbers 1-9 on each side with no repetition

It was created in 2006 by some guy named Jay Horowitz in Ohio. You can buy it at Barnes and Noble and some other places. In what follows we briefly describe how to solve it…
Of course there are lots of variations, including cubes with 4x4x4, and naming variations are Sodokube, Roxdoku. If you want to solve it you need to realize there are a few different
variations on the cube, so depending which one you have, the solution
will be slightly different.

Step 1: Familiarize yourself with solving a Rubik’s Cube. If you
don’t know how to solve the Rubik’s cube, then you will have a LOT of
trouble with the Sudokube (trust me!).

Step 2: Note the centres of each face of your cube. Some cubes
have 5’s in all the centres, others have varying numbers. As in the
Rubik’s cube, these centres will be fixed points and stay in place when
you do the “moves”.

Step 3: If you have the Rubik’s cube algorithm memorized, you should now have no trouble at all solving the cube!!

The end!

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Funny students and tests

More funny exam answers…

Nice… and unusual (xkcd reference btw):
 hoverboard velociraptor xkcd test exam reference
Good answer!
probability test exam question fail

Name a pair of vertical angles… indeed…
pair of vertical angles exam test fail

Well… it was a nice try…
virtual real test exam fail

A whale! Hmm… guess we’ll accept that…
whale picture drawn on test exam fail

Beer-Lambert Law…
beer lambert law test exam

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Dirty math post by Tanya Khovanova

Ya… so…
Tanya Khovanova has a dirty post on her math blog:

The Dirtiest Math Problem Ever (Rated R)

It has to do with what she calls the condom puzzle. Basically, it’s a variation of the glove problem:

Suppose there are “m” doctors and “n” patients (with “n<=m”). There are “mn” combination’s of examinations that pair doctors/patients. How many surgical gloves are needed so that no doctor wears a glove contaminated by a patient, and no patient is exposed to a glove worn by another doctor?

Of course “mn” is an upper bound, but the minimum number is much smaller (can you see why?).

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Check out “Not So Humble Pi” math comic

Check out this comic about math:

pi-color-cartoon-01.jpgIt’s called Not So Humble Pi … apparently the guy is going to be releasing a new batch of comics on November 1st, 2009, and will post one each day!

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