How can one calculate $(-4339 \cdot 8559) \text{ mod } 43$ without a calculator?
I know that the solution is 8, but just because i used a calculator.
What is the correct way when trying to calculate modulo with big numbers? I know Fermats little theorem, but we can't apply it here.
Best Answer
Look for large, but easy to find, multiples of 43 that are close to the numbers you have. Then you can reduce each factor mod 43 and multiply what's left.