IGCSE NUMBER SYSTEMS (Computer Science)
– Binary system
Binary number system is chosen because a computer is made of switches
which can only be in two positions that is, ON and OFF. Therefore, binary
number system is chosen as 1 represents ON and 0 shows OFF. (note: switches
use logic gates to store and process data)
The binary number system is a base 2 number system given it only uses 2
numbers.
Each digit has a weight factor of 2 raised to a power.
– Denary system
The denary number system is a base 10 number system given it uses 10 values-
0 to 9.
Each digit has a weight factor of 10 raised to a power.
– Hexadecimal system and its uses
The hexadecimal number system is made of 16 digits, i.e 0-9 and A-F.
Moreover, each digit has a weight factor of 16 raised to a power.
The hexadecimal system or ‘hex’ is easier to read and understand for humans
because one hex digit represents 4 binary digits.
4 uses of the hexadecimal number systems:
° Error codes ( refer to the memory location of the error )
° HTML color codes ( color codes in 6 hex digits showing red, green and blue )
° IPv6 addresses ( it is a 128 bit address broken into 16 chunks, shown as hex
digits )
° MAC addresses ( this refers to the NIC and uniquely identifies a device on a
network, it is made of 48 bits broken into 6 groups of 2 hex digits )
CONVERSION
– Converting binary to denary
Step 1: Create a binary number line
2^5 2^4 2^3 2^2 2^1 2^0
4 2
32 16 8 1
– Binary system
Binary number system is chosen because a computer is made of switches
which can only be in two positions that is, ON and OFF. Therefore, binary
number system is chosen as 1 represents ON and 0 shows OFF. (note: switches
use logic gates to store and process data)
The binary number system is a base 2 number system given it only uses 2
numbers.
Each digit has a weight factor of 2 raised to a power.
– Denary system
The denary number system is a base 10 number system given it uses 10 values-
0 to 9.
Each digit has a weight factor of 10 raised to a power.
– Hexadecimal system and its uses
The hexadecimal number system is made of 16 digits, i.e 0-9 and A-F.
Moreover, each digit has a weight factor of 16 raised to a power.
The hexadecimal system or ‘hex’ is easier to read and understand for humans
because one hex digit represents 4 binary digits.
4 uses of the hexadecimal number systems:
° Error codes ( refer to the memory location of the error )
° HTML color codes ( color codes in 6 hex digits showing red, green and blue )
° IPv6 addresses ( it is a 128 bit address broken into 16 chunks, shown as hex
digits )
° MAC addresses ( this refers to the NIC and uniquely identifies a device on a
network, it is made of 48 bits broken into 6 groups of 2 hex digits )
CONVERSION
– Converting binary to denary
Step 1: Create a binary number line
2^5 2^4 2^3 2^2 2^1 2^0
4 2
32 16 8 1
