1. The problem statement, all variables and given/known data In Z mod 5, compute (a + b)5. 2. Relevant equations 3. The attempt at a solution Noticing that (a+b)5 = a5+5(a4*b+2*a3*b2+2*a2*b3+a*b4)+b5. Since 5=0 in Z mod 5, it follows that 0(a4*b+2*a3*b2+2*a2*b3+a*b4)=0 and hence (a+b)5=a5+b5. I am just wondering if it is correct for me to say 5=0 in Z mod 5 and just substitute 0 in for 5?