In the decimal number system (what we normally use), the first number (on the right!) is how many ones we have, the second is how many tens, and the third is how many hundreds. So with 347, we have 7 ones plus 4 tens plus 3 hundreds.
With octal (also called base 8), we still have ones on the far right, then eights (instead of tens), then sixty-fours (instead of hundreds). So oct245 would be 5 + 4x8 + 2x64, or 165 in decimal.
So oct31 is three eights plus one, or twenty-five in decimal.
no subject
In the decimal number system (what we normally use), the first number (on the right!) is how many ones we have, the second is how many tens, and the third is how many hundreds. So with 347, we have 7 ones plus 4 tens plus 3 hundreds.
With octal (also called base 8), we still have ones on the far right, then eights (instead of tens), then sixty-fours (instead of hundreds). So oct245 would be 5 + 4x8 + 2x64, or 165 in decimal.
So oct31 is three eights plus one, or twenty-five in decimal.