Question

Add in Octal

Answer 1

In octal number system we have numbers from 0 to 7. A octal number is denoted by base 8. The addition of octal numbers is similar to addition of decimal numbers. But the only difference is, in decimal system we have numbers from 0 to 9, So while adding to numbers the sum can go upto 9. Where as in octal the sum of any two numbers can go only upto 8 and the remaining is considered as carry.

Let us understand this with an example.Consider two octal numbers 162 and 537 with bases 8 since we are dealing with octal numbers.

Method 1)

The addition is very similar to normal decimal addition. But after two numbers are added, the sum we get is decimal. So if the sum is greater than 8 we have to convert it into octal(base 8) by dividing the sum with 8. I have shown this process in step one.

Method 2 ) We can add octal numbers using octal additiont table.

Observe the above table. When you are adding two octal numbers, see the first number in the first row and second number in the first column. The number pointing that pair is the sum of those two numbers in octal. If the sum is in two digits, then first digit is sum and the second digit is carry.

Note : In the octal addition table you wont find numbers greater than 7. i.e 8,9. There will be only octal numbers in octal addition table. ( i.e 0,1,2,3,4,5,6,7) .

However I prefer Method 1 over method 2 since we do not carry this table with use every time nor we can draw one whenever we need it.

Hope this answer helps you.

Thank you :)