What is 9999999999999999999*9999999999999999999?
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 ...
(1020)2 - 2·1020 + (-1)2 Slight correction ......
1040 - 2 * 1020 +1