# How computers see the world

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.
• # Converting from binary to denary

## 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:

ThousandsHundredsTensUnits (1000s) (100s) (10s) (1s)

### Working out the value of 1024

Thousands (1000s)Hundreds (100s)Tens (10s)Units (1s) 1 0 2 4 1 × 1000 + 0 × 100 + 2 × 10 + 4 × 1

## Converting from binary to denary

To convert a binary number to denary, start by writing out the binary place values. In denary, the place values are 1, 10, 100, 1000, etc – each place value is 10 times bigger than the last. In binary,

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# How computers see the world

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.
• # Converting from binary to denary

## 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:

ThousandsHundredsTensUnits (1000s) (100s) (10s) (1s)

### Working out the value of 1024

Thousands (1000s)Hundreds (100s)Tens (10s)Units (1s) 1 0 2 4 1 × 1000 + 0 × 100 + 2 × 10 + 4 × 1

## Converting from binary to denary

To convert a binary number to denary, start by writing out the binary place values. In denary, the place values are 1, 10, 100, 1000, etc – each place value is 10 times bigger than the last. In binary,