Topic one number basis we are used to using the decimal system. In this system each digit is represented using a number between zero and nine. This gives 10 different possibilities for each digit. And therefore this system can also be referred to his base 10. We use this every day without thinking about it. And most of the numbers you come across each day will be in the decimal system, whether they are written down or spoken aloud.

There are however different number systems and we must be familiar with two of them. The first is called binary and is also known as base two. In this system, each digit can only be represented by two different numbers hence base two. This is the language that computer systems use to operate. Another number system is called hexadecimal. In this system, each digit can be represented by 16 different possibilities and this therefore is known as base 16.

Quick question for you to try. If each of the digits in a decimal number are represented by a value from zero to nine, what are the values that are used to represent the digits in a binary system? Pause the video if you need to think about your answer. Second question for you to try. What values are used to represent each of the digits in hexadecimal if there are 16 possibilities? Pause the video and write down your answer.

As you can see, after the number nine letters are used to represent double digit numbers up to 15