Calculate the number of integers from 1 to 180 that are co-prime to 180. Then calculate 7^98mod180. I have answers for this but I'm unsure whether they are correct.

Question

anonymous · Answer

So you have two questions that's right?

anonymous · Answer

yes but i think the first helps answer the second perhaps?

anonymous · Answer

For the first one $ φ(180) =\color{red}{  48} $ and for the second one use Fermat Euler theorem $$ 7^{98} \equiv  7^2 \equiv \color{red}{ 49} \pmod {180} $$

Answers are in color red.

anonymous · Answer

Yes brilliant thank you so much! :)