Prime numbers can only be divided by 1 and itself. To check whether a number is a prime number or not, it must first be divided by 2. If the number can be divided by 2 and remains a whole number, it is not a prime number. Once divided by 2, if the number is not a whole number, the number should then be divided by 3, 5, 7 and 11. If the number comes out a whole number when divided by the remaining numbers listed, then it is not a prime number. If the number is not whole number still, then it is a prime number. For example, 2, 3, 5, 7, 11, 13, 17, 19, 23 and 29 are prime numbers by the rules listed above. A quick fact; there are only two prime numbers that end with a 2 or a 5, namely 2 and 5.
Some interesting facts about math and numbers:
- The search engine 'Google' actually took it's name from the misspelling of a very large number, googol.
- Math equations were once written out in words because most math symbols weren't invented till the 16th century.
- Not frequently heard of, an icosagon is a shape with 20 sides.