**1.**The word “hundred” comes from the old Norse term, “hundrath”, which actually means 120 and not 100.

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

**3.**Most mathematical symbols weren’t invented until the 16th century. Before that, equations were written in words.

**4.**From 0 to 1000, the only number that has the letter “a” in it is “one thousand”.

**5.**Every odd number has an “e” in it.

**6.**Over 2000 years ago, Eratosthenes estimated the Earth’s circumference using math, without ever leaving Egypt, and he was accurate to within 2%!

**7.**Markings on animal bones indicate that humans have been doing math since around 30,000BC.

**8.**Zero is not represented in Roman numerals.

**9**. -40 °C is equal to -40 °F.

**10.**The symbol for division (i.e.÷) is called an obelus.

**11.**2 and 5 are the only prime numbers that end in 2 or 5.

**12.**A ‘jiffy’ is an actual unit of time. It means 1/100th of a second.

**13.**If you shuffle a deck of cards properly, it’s more than likely that the exact order of the cards you get has never been seen before in the whole history of the universe!

**14.**Mathematics is important in many different types of jobs, including engineering, business, science, medicine and more.

**15.**It is believed that Ancient Egyptians used complex mathematics such as algebra, arithmetic and geometry as far back as 3000 BC.

**16.**What comes after a million, billion and trillion? Why a quadrillion, quintillion, sextillion, septillion, octillion and nonillion of course.

**17.**The name of the popular search engine ‘Google’ came from a misspelling of the word ‘googol’, which is a very, very large number (the number one followed by one hundred zeros to be exact).

**18.**The number Pi (the ratio of the circumference to the diameter of a circle) can’t be expressed as a fraction, this means it is an irrational number. When written as a decimal it never repeats and never ends. Here is Pi written to 50 decimal places: 3.14159265358979323846264338327950288419716939937510

## Try this out!

The answer is always

Starting with any four digit number (that has at least two different digits) just follow the following steps:

1. Arrange the digits of the four digit number in descending/ascending order to make the largest and smallest numbers possible.

2. Subtract the smaller number from the larger one.

3. Take the answer and repeat the process.

Eventually you'll end up at 6174 or 'Kaprekar's Constant'. Just as remarkable, it never takes more than seven stages to get there.

Picking a number at random, let's try 4551, for instance.

**6174!!!**Starting with any four digit number (that has at least two different digits) just follow the following steps:

1. Arrange the digits of the four digit number in descending/ascending order to make the largest and smallest numbers possible.

2. Subtract the smaller number from the larger one.

3. Take the answer and repeat the process.

Eventually you'll end up at 6174 or 'Kaprekar's Constant'. Just as remarkable, it never takes more than seven stages to get there.

Picking a number at random, let's try 4551, for instance.

**Stage 1**: 5541-1455 = 4086**Stage 2**: 8640 - 0468 = 8172**Stage 3**: 8721 - 1278 = 7443**Stage 4**: 7443 - 3447 = 3996**Stage 5**: 9963 - 3699 = 6264**Stage 6**: 6642 - 2466 = 4176**Stage 7**: 7641 - 1467 = 6174