i am learning about modulo and congruencies in class and i am seeking some help.

i need to find a complete residue system mod 11 consisting of odds only.

show that every pos int. n, 7^n congruent to 1+6n (mod36)

find the least residue of (n-)! mod n for several values of n. find a rule but no need for a proof.

here is what i know so far...

with the least residue problem, i know that a=mq+r w/ 0<=r<1 then r is the least residue, so it is like the remainder correct? any one offer further advise to help w/ this?

to find out the conplete resideu system of mod 11 means that m divides (a-b) where a and b are congruent to each other. any other help?

the second problem i really don't know how to do but would like help! please.