0
Question: Which of the following are reduced modulo residue systems modulo 18?
$a. 1,5,25,125,625,3125$
$b. 5, 11, 17, 23, 29, 35$
$c. 1, 25, 49, 121, 169, 289$
$d. 1, 5, 7, 11, 13, 17$
Attempt: Our mod n is mod 18, so n = 18. Now, we need to remove the integers that aren't prime to n. Now, ...