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In this chapter you will learn about:
§ Non-positional number system
§ Positional number system
§ Decimal number system
§ Binary number system
§ Octal number system
§ Hexadecimal number system
Learning Objectives Learning Objectives
(Continued on next slide)
Two types of number systems are:
§ Non-positional number systems
§ Positional number systems
Number Systems Number Systems
§ Characteristics
§ Use symbols such as I for 1, II for 2, III for 3, IIII
for 4, IIIII for 5, etc
§ Each symbol represents the same value regardless
of its position in the number
§ The symbols are simply added to find out the value
of a particular number
§ Difficulty
§ It is difficult to perform arithmetic with such a
number system
Non-positional Number Systems Non-positional Number Systems
§ The value of each digit is determined by:
1. The digit itself
2. The position of the digit in the number
3. The base of the number system
( base = total number of digits in the number
system)
§ The maximum value of a single digit is
always equal to one less than the value of
the base
Positional Number Systems Positional Number Systems
(Continued from previous slide..)
Characteristics
§ A positional number system
§ Has 10 symbols or digits (0, 1, 2, 3, 4, 5, 6, 7,
8, 9). Hence, its base = 10
§ The maximum value of a single digit is 9 (one
less than the value of the base)
§ Each position of a digit represents a specific
power of the base (10)
§ We use this number system in our day-to-day
life
Decimal Number System Decimal Number System
(Continued on next slide)
Characteristics
§ A positional number system
§ Has only 2 symbols or digits (0 and 1). Hence its
base = 2
§ The maximum value of a single digit is 1 (one less
than the value of the base)
§ Each position of a digit represents a specific power
of the base (2)
§ This number system is used in computers
Binary Number System Binary Number System
(Continued on next slide)
Example
101012 = (1 x 2^4 ) + (0 x 2^3 ) + (1 x 2^2 ) + (0 x 2^1 ) x (1 x 2^0 ) = 16 + 0 + 4 + 0 + 1 = (^2110)
Binary Number System Binary Number System
(Continued from previous slide..)
§ Bit stands for bi nary digi t
§ A bit in computer terminology means either a 0 or a 1
§ A binary number consisting of n bits is called an n-bit
number
Bit Bit
Characteristics
§ A positional number system
§ Has total 8 symbols or digits (0, 1, 2, 3, 4, 5, 6, 7).
Hence, its base = 8
§ The maximum value of a single digit is 7 (one less
than the value of the base
§ Each position of a digit represents a specific power of
the base (8)
Octal Number System Octal Number System
(Continued on next slide)
Characteristics
§ A positional number system
§ Has total 16 symbols or digits (0, 1, 2, 3, 4, 5, 6, 7,
8, 9, A, B, C, D, E, F). Hence its base = 16
§ The symbols A, B, C, D, E and F represent the
decimal values 10, 11, 12, 13, 14 and 15
respectively
§ The maximum value of a single digit is 15 (one less
than the value of the base)
Hexadecimal Number System Hexadecimal Number System
(Continued on next slide)
§ Each position of a digit represents a specific power
of the base (16)
§ Since there are only 16 digits, 4 bits (
4
= 16) are
sufficient to represent any hexadecimal number in
binary
Example
1AF 16 = (1 x 16
2
) + (A x 16
1
) + (F x 16
0
= 1 x 256 + 10 x 16 + 15 x 1
Hexadecimal Number System Hexadecimal Number System
(Continued from previous slide..)
Example 4706
=?
47068 = 4 x 8 3
- 7 x 8 2
- 0 x 8 1
- 6 x 8 0 = 4 x 512 + 7 x 64 + 0 + 6 x 1 = 2048 + 448 + 0 + 6 = 2502 10 Common values multiplied by the corresponding digits Sum of these products (Continued from previous slide..) Converting a Number of Another Base to a Decimal Number Converting a Number of Another Base to a Decimal Number
Division-Remainder Method Step 1: Divide the decimal number to be converted by the value of the new base Step 2: Record the remainder from Step 1 as the rightmost digit (least significant digit) of the new base number Step 3: Divide the quotient of the previous divide by the new base Converting a Decimal Number to a Number of Another Base Converting a Decimal Number to a Number of Another Base (Continued on next slide)