Thread: Simple arithmetic in base 8

This problem has been solved. Thanks to all who helped.

How do I *manually* (not use a calculator) multiply in a base other than 10, say base 8? Say I have 647(base 8) and 251(base 8) how do I multiply 647*251 and get the right answer in base 8?

Seems like this should be real simple. But I get two answers depending upon how I do it.

Here's a link that describes how to multiply in other bases:
Multiplying numbers in bases other than 10 - Math Central

And a multiplication table for base eight:
Multiplication Tables for Other Bases

I would just convert the numbers into decimal; it's easier with smaller numbers and less careless errors will probably be made.

I think it would be easier for us to convert both the numbers into base 10 and reconvert the answer back in base 8.