Question

Which number should be added to 6659 to make it a perfect square?

Answer 1

The answer is 65.
6659 =
When we take square root of 6659 we get nearest as 81.
Now 81^2 = 6561
And 82^2 = 6724
81^2 < 6659 < 8^2 =
6561 < 6659 < 6724 =
6724 - 6659 = 65
65 must be added to 6659 then it is a perfect square.
6659 + 65 = 6724
Square root of 6724 = 82