Getting primitive roots of 14.
For example, if n = 14 then the elements of Zn× are the congruence classes {1, 3, 5, 9, 11, 13}; there are φ(14) = 6 of them. The order of 1 is 1, the orders of 3 and 5 are 6, the orders of 9 and 11 are 3, and the order of 13 is 2. Thus, 3 and 5 are the primitive roots modulo 14. Question is how you get that possible candidates to primitive roots are {1, 3, 5, 9, 11, 13}?
For example which are possible candicates of primitive root of modulo 10 and how do you get them?