Octal Place Values — TechKnowSurge

About this interactive

Octal is base 8. It uses eight digits, 0 to 7, and each column is worth eight times the one to its right: 1, 8, 64, 512, 4,096. Counting works the same way as in binary, decimal and hexadecimal. When a column passes its largest digit, 7, it resets to 0 and carries 1 into the next column, so after 7 comes 10 (one eight, no ones). To convert octal to decimal, multiply each digit by its column's value and add: octal 2643 is 2 x 512 + 6 x 64 + 4 x 8 + 3 x 1 = 1,443. Type each answer as digits in decimal unless the question asks for an octal number. Commas are optional.

What you'll learn

Count in octal, give the value of each octal column, and convert an octal number to decimal by its place values, comparing octal's columns with binary, decimal and hexadecimal

Aligned to

CompTIA Tech+

1.1 Compare and contrast notational systems.

Key terms

Octal: A base-8 number system using digits 0 through 7, where each digit represents exactly three binary bits; commonly used in Unix and Linux file permission notation because a three-bit permission group (read, write, execute) maps cleanly to a single octal digit.
Base: The number of unique digits used in a positional numbering system, which also determines the value of each place position.
Positional Place Value: The value of a digit determined by its position within a number, where each position represents a power of the number system's base.

Topics

Octal Number Systems Interactive Calculation

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