Any number can be a base; however, only a few are common on computers. The ones we discussed previously (hexadecimal, decimal, octal, and binary) are the most common on computer systems.

Octal numbers, where octal is the technical word for base 8, are a largely obsolete way to represent numbers on a computer. Octal demonstrates how we can use the same method for any base in the same way we did for binary, except with the root of 8. Also, note that every three binary digits become a single octal digit, making translation between octal and binary easier. For example:

  • 0o3 = 0b011 = 3
  • 0o13 = 0b001011 = 11
  • 0o713 = 0b111001001 = 459

One key we can pick up on is 8 is equivalent to 2 cubed, and thus, and number value for an octal digit could in turn be represented as 3 binary numbers. Looking at our last example: 0o 7 1 3, we can separate all 3 digits out into individual 3 digit binary digits like 0b 111 001 001 to find the binary representation.

Every time we have an octal numeral (digit), we have 3 binary digits. This fact makes translation uncomplicated. Sometimes, we may add a leading 0 to make even groups of 3. That will not affect the result of mathematics with an integer.



What is the highest octal numeral (digit) in any column of an octal number?

Assign the value to checkpoint_1 in the code editor.


Is the number “1” odd in octal? Answer with “odd” or “even”.

Assign the value to checkpoint_2 in the code editor.

Take this course for free

By signing up for Codecademy, you agree to Codecademy's Terms of Service & Privacy Policy.
Already have an account?