i just can't finish up these proofs but i have my ideas written down on the bottom. also, i have what i think is right written down, but it IS A LOT of stuff to type. can anyone point me in the correct direction to go? i need to show that if gcd(a,n)=(a-1,n)=1, then 1+a+...+a^0 mod n show (m,n)=1 then m 1 mod (mn) show if m and k are positive integers then (^k)=m^k-1(m) what i know so far: the second one can use fermat's little theroem correct? if a==0 mod b and b==0 mod a then => ab==0 mod(ab) the third one is just playing with my brain, i honestly do not know anywhere to start it. the first question says what a,n are relatively prime, and a-1,n are also relatively prime. so, if any a raised to a power, that a is == to 0, mod n. can anyone give me a "hint"? thank you!! p.s. does my LaTeX look good? feel free to tell me and all.