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Whether you're a math whiz or not, there are some pretty cool number theories, beliefs and coincidences to appreciate. How down with digits are you?

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Question 1 of 10

What's the only number left that mathmeticians don't know how to express as the sum of three cubes?

33

42

It took more than 60 years, but mathemetician Andrew Booker finally figured out how to express 33 as the sum of three cubes (33 = x³+ y³+ z³). The only number left to be worked out is 42, which if you're a fan of "The Hitchhiker's Guide to the Galaxy" just adds a whole extra level of "wow."

111

Question 2 of 10

What number's mystical significance might have started with a story from author William Burroughs?

47

13

23

The famed writer may have kicked off the obsession with the number 23 thanks to his short story "23 Skidoo," inspired by a series of bizarre occurrences he had involving the number. There's even a Facebook page, "23rdians," populated by people who believe in 23's significance.

Question 3 of 10

After age 30, how much more likely is the average person to die?

The risk of death doubles every eight years.

Actuary Benjamin Gompertz developed a "mortality equation" in 1825 which is still used today to help insurance companies figure out how to buy and sell annuities. He calculated that the odds of a person dying roughly doubles every eight years.

The death risk doesn't take a big leap until age 50.

The risk of death triples after age 40.

Question 4 of 10

If someone asks you to guess what their favorite number is, which of these should you guess?

3

7

You might have the most luck guessing number 7. A 1971 study, known as the "blue-seven" phenomenon, found that 30 percent of respondents said their favorite number was 7, while 40 percent said their favorite color was blue! This was consistent across countries.

5

Question 5 of 10

Where did fear of the number 666 originate?

"Carrie" by Stephen King

the New Testament's Book of Revelation

One verse in particular reads, “One who understands can calculate the number of the beast, for it is a number that stands for a person. His number is six hundred and sixty-six” (Rev. 13:18). The beast refers to the Antichrist.

Dante's "Inferno"

Question 6 of 10

What type of numbers are often used to complete secure credit card transactions?

prime numbers

Prime numbers, which are divisible only by one and itself, appear random, and are thusly used to encrypt information exchanged over the internet.

irrational numbers

square numbers

Question 7 of 10

What is a "perfect number"?

a perfectly symmetrical number, like 8

a positive integer equal to the sum of its proper divisors

The smallest of all the perfect numbers is 6, which is the sum of its divisors, 1, 2 and 3.

an answer which has no remainder at the conclusion of a division problem

Question 8 of 10

What's cool about pi?

No matter the size of the circle, the ratio of circumference to diameter will always equal 3.14.

Pi is the ratio of the circumference of a circle to its diameter. The amazing thing is whether you're measuring a planet or a tennis ball, the number will always be 3.14.

As a circle doubles in size, pi will also double.

It tastes great with a cup of coffee.

Question 9 of 10

Evolutionary biologist Robin Dunbar said the human brain can't handle more than this number of friends:

150

Dunbar's number as its called, was based on his research showing that hunter-gatherer societies were comprised around 150 people.

100

200

Question 10 of 10

Which number is a homonym for the word "death" in Chinese?

11

13

4

In Chinese, the word for "death" sounds like the pronunciation for number 4. Many buildings in China will skip a fourth floor just like buildings in the U.S. won't have a 13th floor.

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