Students will learn the definition for the order of an element in a group. They will also learn what it means for an element to have finite or infinite order. Then they'll see examples of groups and asked to determine the order of various elements. Here's a video on all that. Finally, students will see a proof of the following theorem: Let \(G\) be a group, \(g \in G,\) \(n \in \mathbb{N}.\) Prove that if \(g^n = e,\) then \(o(g)\) divides \(n.\) A proof can be seen here. Understanding the proof requires students to know the division algorithm.
TODO: Is the converse true?