I read a brainteaser once which asked how do you calculate the sqaure root of a no. on a regular calci without using the root function?Obviously,I missed the next issue which posted the answers. Repeat,I don't know the solution.I just wanted to know if there was a procedure to do so.
Wiki to the rescue: https://en.wikipedia.org/wiki/Methods_of_computing_square_roots Should keep you occupied for a few hours. :