# What is Octal Number system? DLD digital logic design

By Prof. Fazal Rehman Shamil

### What is Octal Number system?

• The Octal number is a number system with base 8 and digits range is from 0 to 7.
• Octal number system was used in past and now a days it is not used in modern digital systems.
• Each Octal Number digit is basically 2 3=8 and represent a 3-bit Binary Number.
• Binary Numbers and the Octal equivalents are discussed in the table below;
 Decimal Binary Octal 0 000 0 1 001 1 2 010 2 3 011 3 4 100 4 5 101 5 6 110 6 7 111 7

Table: Octal Equivalents of Binary  and decimal Numbers

## Counting in Octal Number System

• The maximum value that can be represented by a one single octal digit is 7 because it starts from 0 and octal means 0 to 8.
• Decimal 8 can be represented by a combination of 108.
• The subscript 8 in 108 indicates that the number is Octal.
• Some of the Octal Numbers for Decimal numbers 8 to 30 are discussed in table below;
 Decimal Octal Decimal Octal Decimal Octal 8 10 16 20 24 30 9 11 17 21 25 31 10 12 18 22 26 32 11 13 19 23 27 33 12 14 20 24 28 34 13 15 21 25 29 35 14 16 22 26 30 36 15 17 23 27 31 37 Table: Octal Numbers upper than 0 to 7

Thanks: Hopefully you are now able to understand the octal number systems Prof.Fazal Rehman Shamil (Available for Professional Discussions)
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