The base 8 notational system for representing real numbers. The digits used are 0, 1, 2, 3, 4, 5, 6, and 7, so that 
(8 in base 10) is represented
as 
(
) in base 8. The following table gives
the octal equivalents of the first few decimal numbers.
| 1 | 1 | 11 | 13 | 21 | 25 |
| 2 | 2 | 12 | 14 | 22 | 26 |
| 3 | 3 | 13 | 15 | 23 | 27 |
| 4 | 4 | 14 | 16 | 24 | 30 |
| 5 | 5 | 15 | 17 | 25 | 31 |
| 6 | 6 | 16 | 20 | 26 | 32 |
| 7 | 7 | 17 | 21 | 27 | 33 |
| 8 | 10 | 18 | 22 | 28 | 34 |
| 9 | 11 | 19 | 23 | 29 | 35 |
| 10 | 12 | 20 | 24 | 30 | 36 |
The song "New Math" by Tom Lehrer (That Was the Year That Was, 1965) explains how to compute 
in octal. (The answer is 
.)
