AS Computing
Unit 1.4 Data Representation and Data Types
Data can be represented in many forms. The most basic form is what we call Binary. Binary is also
known as Base-2 and only allows for 1’s ad 0’s.
So for example;
124 in binary is 01111011:
128 64 32 16 8 4 2 1
0 1 1 1 1 0 1 1
Computers use binary because at their bases computers are just switches. So, computers can
understand one of two conditions: On and Off. We use 1 and 0 to represent these states. Another
way of representing data is using hexadecimal (Base-16), this is used because it easier for humans to
read. Humans are thought to have started to use Base-10 (Decimal) because we have ten fingers and
thumbs.
Binary
Some examples of Decimal -> Binary number and vice versa conversions are:
1) What is 1 in 8-Bit Binary?
128 64 32 16 8 4 2 1
0 0 0 0 0 0 0 1
1 is 00000001 in 8-Bit Binary.
2) What is 00100101 in Decimal
128 64 32 16 8 4 2 1
0 0 1 0 0 1 0 1
00100101 in decimal is 32+4 +1 which is 37 .
The largest number we can represent in 8-Bit binary is 255, which is the result of the conversion of
the number 11111111 to decimal. To represent larger numbers, we would need a larger store of
numbers e.g. a 16-Bit decimal number. The numbers in an 8-Bit binary conversion table (Show
above) double each time as you go from right to left from 1 to 128.
Data Types
There are many data types that we use to represent different types of data inside computers. We
only need to know about a few of them. The ones that we need to know about are:
Data Type Example Usage
String “Hello” Names, addresses etc.
Real Number 0.234 Decimals, Currency
Integer 63 Age, whole numbers
Boolean True True or False
Character ‘E’ One character
Page |1 Luca Passariello AS Computing
Unit 1.4 Data Representation and Data Types
Data can be represented in many forms. The most basic form is what we call Binary. Binary is also
known as Base-2 and only allows for 1’s ad 0’s.
So for example;
124 in binary is 01111011:
128 64 32 16 8 4 2 1
0 1 1 1 1 0 1 1
Computers use binary because at their bases computers are just switches. So, computers can
understand one of two conditions: On and Off. We use 1 and 0 to represent these states. Another
way of representing data is using hexadecimal (Base-16), this is used because it easier for humans to
read. Humans are thought to have started to use Base-10 (Decimal) because we have ten fingers and
thumbs.
Binary
Some examples of Decimal -> Binary number and vice versa conversions are:
1) What is 1 in 8-Bit Binary?
128 64 32 16 8 4 2 1
0 0 0 0 0 0 0 1
1 is 00000001 in 8-Bit Binary.
2) What is 00100101 in Decimal
128 64 32 16 8 4 2 1
0 0 1 0 0 1 0 1
00100101 in decimal is 32+4 +1 which is 37 .
The largest number we can represent in 8-Bit binary is 255, which is the result of the conversion of
the number 11111111 to decimal. To represent larger numbers, we would need a larger store of
numbers e.g. a 16-Bit decimal number. The numbers in an 8-Bit binary conversion table (Show
above) double each time as you go from right to left from 1 to 128.
Data Types
There are many data types that we use to represent different types of data inside computers. We
only need to know about a few of them. The ones that we need to know about are:
Data Type Example Usage
String “Hello” Names, addresses etc.
Real Number 0.234 Decimals, Currency
Integer 63 Age, whole numbers
Boolean True True or False
Character ‘E’ One character
Page |1 Luca Passariello AS Computing
