Question

what is the least number that should be subtracted from 385 to get a perfect square? also find square root of the number

Answer 1

Let us check the squares of some numbers, 
starting from 15.
15 square=225
16 square=256
17 square=289
18 square=324
19 square=361
20 square=440

as 20's square is more than 385 we have to take 19's square 
385-361=24
so 24 is the least number that should be subtracted from 385 to get a perfect square 
and the square root of 361 is 19