+91 Just note that in base 8, anything above 8 gets carried to the next place value. Eg., 4 + 5 = 11, as 4 + 5 is 9, and 8 out of that 9 is carried to the 10s place to become a 1.
Therefore,
4 base(8) + 7 base(8) = 13 base(8)
This is because 7 + 4 = 11, and taking away 8 we get 3. The 3 stays in the unit's place, and the 8 that we took away becomes the 1 in the tens place.
(13 base(8) is just 11 in base(10))
