Name: Specialization: Computer Systems Servicing
Track and Strand: TVL-ICT Subject: CSS II
NUMBER SYSTEMS
Number systems are also called numeral systems. Number System is any notation that represents
numerals or numbers.
1. Decimal – Most common number system, the basic of how we count, as we know it. It has a base
or radix of 10.
2. Binary – Computer machine language. It means on the machine level, this is the only recognizable
data to the computer. It has base or radix of 2.
3. Octal – Group of binary digits intro groups of three called octets. Thus, 23 is equal to 8, deriving the
name octal. 8 is its radix or base, represented by the symbols 0-7.
4. Hexadecimal – This number system is a spin off from octal system. It has a radix or base of 16.
DECIMAL
1 11 21 … 91 … 991 … 9991
2 12 22 … 92 … 992 … 9992
3 13 23 … 93 … 993 … 9993
4 14 24 … 94 … 994 … 9994
5 15 25 … 95 … 995 … 9995
6 16 26 … 96 … 996 … 9996
7 17 27 … 97 … 997 … 9997
8 18 28 … 98 … 998 … 9998
9 19 29 … 99 … 999 … 9999
10 20 30 … 100 … 1000 … 10000
84310 = (8 x 102) + (4 x 101) + (3 x 100)
= (8 x 100) + (4 x 10) + (3 x 1)
= 800 + 40 + 3
= 843
BINARY
OCTAL
Octal Decimal Octal Decimal
0 0 10 8
1 1 11 9
2 2 12 10
3 3 13 11
Base
2
Equivalen
t
Decimal Binary
201 0 0000
212 1 0001
224 2 0010
238 3 0011
2416 4 0100
2532 5 0101
2664 6 0110
27128 7 0111
28256 8 1000
29512 9 1001
2n… … …
