Split each factor: \(\mathbb{Z}_6\cong\mathbb{Z}_2\times\mathbb{Z}_3\) and \(\mathbb{Z}_{10}\cong\mathbb{Z}_2\times\mathbb{Z}_5\). The total order is \(60\), and the factor \(\mathbb{Z}_2\) appears twice.
Every finite abelian group \(G\) is isomorphic to a direct product of cyclic groups \(\mathbb{Z}_{p^k}\), with \(p\) prime and \(k\ge1\), unique up to order.