How to convert
For converting octal number to decimal, multiply each digit by 8n, where n is the position of the digit from the right, starting at 0. Then sum up the results of each multiplication.
abc2 = (a×82 + b×81 + c×80)10
568 = (5*81 + 6*80)10 = 4610
4678 = (4*82 + 6*81 + 7*80)10 = 31110