## Compute $\langle 5 \rangle$ in integers November 29 2

Compute $\langle 5 \rangle$ in integers. I thought the answer would have been $$\{5^n| \text{ for $n$ in integers }\}$$ However my teacher has marked it $$\{5*n|\text{ for $n$ in integers }\}$$ What have I done wrong?The integers do not form a group