So,
We're going to convert the following number in base 2:
To base 8.
Step 1: Write down the binary number
(011011001)2
Group all the digits in sets of three starting from the far right. Add zeros to the left of the last digit if there aren't enough digits to make a set of three. We obtain:
Now, remember the following equivalences:
Bin: 000 001 010 011 100101110111
Octal:01234567
Therefore,
011 011 001 = 331
And finally: