**Here is the way to do operations on octal and octal conversion into decimal:**

Read the given problem and note down the two octal numbers. Perform all the arithmetic operation using the below rules:

**Addition:** If the sum of the octal number is 7 or less than the basic addition is as it is!. But if the sum is 8 then its taken as 10 and for every increase in number more than 8, the number is added by 1 to 10.

**Subtraction:** Subtraction in octal system is same method as basic subtraction operation method.

**Multiplication:** Multiply the given two octal numbers and get the product. Then go on subtracting the product by 8 till the value less than 8, add that value with the product to get the answer.

**Division:** Divide the dividend with divisor to get the quotient such that the each digits of the quotient. Carry on the repeated division till you get the dividend less than divisor. The quotient is taken as the answer.

**Octal to decimal conversion :** Determine the decimal equivalent of the given octal number, then multiply each of the positional value with digit and add the result.