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1.4 Data Representation and Data Types
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AS ComputingUnit 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
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