Page 12 - 2633 Trackpad Pro V5.1 Class 7

OCTAL NUMBER SYSTEM
A number system made up of eight digits from 0 to 7, is known as the octal number system. When

the octal number system is used, every number is formed using 0,1,2,3,4,5,6 and 7. The base of
the octal number system is 8. It is also known as the base-8 system. Each positioning number
represents the power of base 8. The place value of the digits according to position and weight is
as follows:

Position 2 1 0 -1 -2
.
Weights 8 2 8 1 8 0 8 -1 8 -2

For example: (1763) 8

3
2
1
= (1 x 8 ) + (7 x 8 ) + (6 x 8 ) + (3 x 8 )
0
= (1 x 512) + (7 x 64) + (6 x 8) + (3 x 1)
= 512 + 448 + 48 + 3
= 1011 or (1011) 10

HEXADECIMAL NUMBER SYSTEM
A number system made up of sixteen symbols, 0 to 9, and A to F is known as the hexadecimal
number system. When the hexadecimal number system is used, every number is formed using 0,
1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E and F, where A = 10, B = 11, C = 12, D = 13, E = 14, and F = 15. The base
of the hexadecimal number system is 16. It is also known as the base-16 system. Each position

represents a power of base 16. The place value of the digits according to position and weight is as
follows:

Position 2 1 0 . -1 -2

Weights 16 2 16 1 16 0 16 -1 16 -2

For Example: (2AF) 16

0
1
2
= (2 x 16 ) + (A x 16 ) + (F x 16 )
= (2 x 256) + (10 x 16) + (15 x 1)
= 512 + 160 + 15

= 687

The hexadecimal number system has made the representation of large values easy. The
hexadecimal numbers are used to represent colours on a webpage, that's why programmers
now prefer hexadecimal numbers. Some examples of colour code are:

Red: #FF0000
Green: #00FF00

Blue: #0000FF

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