What is the answer

Question:  What is (10²⁰ - 1) x (10²⁰​ - 1) ?

 

This is a binomial, so it can be simplified as:

                    =  (10²⁰)² - 2·10² + (-1)²

                    =  10⁴⁰ -  2·10² + 1

 

And, if you are really interested, you can finish this ...