Numbers are wonderful things. We use them to measure things, to calculate, and even to convince people. But sometimes you come across a fact about numbers that just sounds too crazy to be true.

**1. Every time you shuffle a deck of cards, chances are that you have put them in an order that has never been seen in the history of the universe.**

Watch the last 5 minutes of the video below to hear the rest of the story

**2. In a room of 23 people, there’s a 50 percent chance that two people have the same birthday**

In a group of people, there are 23 x 22/2 = 253 pairs of people. The chance of any particular pair having different birthdays is 364/365. However, the chance of all pairs having different birthdays is (364/365)^{253}=0.4995. It may seem counterintuitive, but it’s true. If you increase the number of people in the room to 75, then you are almost guaranteed (with a 99.9 percent chance) that at least two people have the same birthday.

**3. People tend to associate odd numbers with males and even numbers with females**

Research done by James Wilkie and Galen Bodenhausen shows that when people are asked to associate the numbers with genders, they tend to associate odd numbers with males and even numbers with females.

In an article published by the Kellogg School of Management at Northwestern University, the researchers described possible reasons for this: The digit 1 is seen as a “single, stand-alone entity,” whereas 2 “suggests togetherness and cooperation—stereotypically feminine qualities.” Our perception of all numbers could relate to these basic ones.

**4. There isn’t enough room on the entire planet to write out a googolplex**

A googol is 1 followed by 100 zeros. A googolplex is 1 followed by a googol zeros, so basically a really big number. It is so big that that if you were to write the whole thing out in books, they would weigh more than our entire planet — far more in fact. They would weigh about 1093 kg, whereas the Earth weighs about 5.972 x 1024 kilograms

**5. There’s no such thing as a boring number in math**

**6. If you look at any particular data set that is long enough, the digit “1” will appear more often than any other**

This fact was first observed by physicist Frank Benford in 1983 and doesn’t only apply to 1. In fact, as the size of the digit goes up, the less frequently it is likely to appear.

Think of a set of addresses for example. They start at 1 and go up to a certain number. The digit 9 will only appear as often as the others if the addresses go up to 9, 99, 999, and so on. Benford’s Law is particularly interesting because it is what we call scale-invariant — it doesn’t matter what units you measure something in. If your data set is big enough, it will always apply.

According to Ian Stewart in “Professor Stewart’s Cabinet of Mathematical Curiosities,” tax collectors use this fact to detect made-up figures in taxes because people will use each digit equally frequently.