The numerical digits we use today such as 1, 2 and 3 are based on the Hindu-Arabic numeral system developed over 1000 years ago.

Different names for the number 0 include zero, nought, naught, nil, zilch and zip.

The smallest ten prime numbers are: 2, 3, 5, 7, 11, 13, 17, 19, 23 and 29.

2 and 5 are the only prime numbers that end with a 2 or a 5.

The golden ratio of approximately 1.618 between two quantities such as lengths often appears in nature (tree branching, uncurling ferns, pine cone arrangements etc) and has been used throughout history to create aesthetically pleasing designs and art works such as Leonardo da Vinci’s Mona Lisa.

Fibonacci numbers are named after Italian mathematician Leonardo of Pisa (better known as Fibonacci) who introduced them to Western Europe after they had earlier been described by Indian mathematicians. They are related to the golden ratio and proceed in the following order: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, .... Can you see the pattern?

The number Pi (the ratio of the circumference to the diameter of a circle) can’t be expressed as a fraction, making it an irrational number. It never repeats and never ends when written as a decimal.

Here is Pi written to 100 decimal places:
3.1415926535897932384626433832795028841971693993751
058209749445923078164062862089986280348253421170679

What comes after a million, billion and trillion? A quadrillion, quintillion, sextillion, septillion, octillion, nonillion, decillion and undecillion.

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

A ‘googolplex’ is the number 1 followed by a googol zeros, a number so ridiculously big that it can’t be written because there literally isn't enough room in the entire universe to fit it in!

Check out some more big numbers.

You might have heard the word ‘infinity’ before or seen its symbol that looks like the number 8 placed on its side. Infinity means a limitless quantity or something that goes on forever. While it’s not really a number like 1, 2 or 3, infinity is often used in math as part of equations and formulas.

111111111 x 111111111 = 12345678987654321

12 + 3 - 4 + 5 + 67 + 8 + 9 = 100

1 x 8 + 1 = 9
12 x 8 + 2 = 98
123 x 8 + 3 = 987
1234 x 8 + 4 = 9876
12345 x 8 + 5 = 98765
123456 x 8 + 6 = 987654
1234567 x 8 + 7 = 9876543
12345678 x 8 + 8 = 98765432
123456789 x 8 + 9 = 987654321

The number 142857 is rather special. When you multiply it the digits found in the answer stay the same, just in a different order. Check it out:

1 x 142857 = 142857
2 x 142857 = 285714
3 x 142857 = 428571
4 x 142857 = 571428
5 x 142857 = 714285
6 x 142857 = 857142

What happens when you multiply it by 7? You get another rather special number:

7 x 142857 = 999999

And it doesn't stop there:

142 + 857 = 999
14 + 28 + 57 = 99

142857 x 142857 = 20408122449
20408 + 122449 = 142857

1 = One
10 = Ten
100 = One hundred
1000 = One thousand
86400 = The number of seconds in a day
1000000 = One million
31556926 = The number of seconds in a year
1000000000 = One billion
7000000000 = The estimated human population on Earth (2011)
1000000000000 = One trillion
1000000000000000 = One quadrillion
1000000000000000000 = One quintillion
1000000000000000000000 = One sextillion
1000000000000000000000000 = One septillion
1000000000000000000000000000 = One octillion
1000000000000000000000000000000 = One nonillion
1000000000000000000000000000000000 = One decillion
1000000000000000000000000000000000000 = One undecillion
1000000000000000000000000000000000000000 = One duodecillion
1000000000000000000000000000000000000000000 = One tredecillion
1000000000000000000000000000000000000000000000 = One quattuordecillion
1000000000000000000000000000000000000000000000000 = One quindecillion
1000000000000000000000000000000000000000000000000000 = One sexdecillion
1000000000000000000000000000000000000000000000000000000 = One septendecillion
1000000000000000000000000000000000000000000000000000000000 = One octodecillion
1000000000000000000000000000000000000000000000000000000000000 = One novemdecillion
1000000000000000000000000000000000000000000000000000000000000000 = One vigintillion

1000000000000000000000000000000000000000000000000000000000000000000
0000000000000000000000000000000000 = One googol (the number 1 followed by 100 zeros)

1000000000000000000000000000000000000000000000000000000000000000000000
0000000000000000000000000000000000000000000000000000000000000000000000
0000000000000000000000000000000000000000000000000000000000000000000000
0000000000000000000000000000000000000000000000000000000000000000000000
000000000000000000000000 = One centillion (the number 1 followed by 303 zeros)

One googolplex = The number 1 followed by a googol zeros (there literally isn't enough room in the universe to write this number).

While not really a number, ‘infinity’ refers to a limitless quantity and is represented by a symbol that looks like the number 8 placed on its side.