# Data Representation

Data representation

There are a number of very common needs for a computer, including the need to store and view data.

Computers use electrical signals that are on or off, so they have to see everything as a series of binary numbers. This data is represented as a sequence of 1s and 0s (on and off). All data that we want a computer to process needs to be converted into this binary format.

What is binary?

Binary is a number system that only uses two digits: 1 and 0. All information that is processed by a computer is in the form of a sequence of 1s and 0s. Therefore, all data that we want a computer to process needs to be converted into binary.

The binary system is known as a ‘base 2’ system. This is because:

• there are only two digits to select from (1 and 0)
• when using the binary system, data is converted using the power of two.

What is binary?

How does it work?

What is the number base for binary?

Understanding denary

People use the denary (or decimal) number system in their day-to-day lives. This system has 10 digits that we can use: 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9.

The value of each place value is calculated by multiplying by 10 (ie by the power of 10). The first few place values look like this:

Working out the value of 1024

Task 2 (Use the information above and the video)

What is denary?

What is the number base for denary?

Exam questions

The memory of a computer contains data and information stored in binary.

1. Explain why computers use binary ( 2 marks)
2. Describe how information is stored in binary (3 marks)