Properties of the multiplication table of $\mathbb{Z}_m$
139659
Find all $n$ with $\!\bmod n\!:\, a\,$ invertible $\Rightarrow a^{-1} \equiv a,\,$ i.e. $a^2\equiv 1$
19310
Identify the ring $\mathbb{Z}[x]/(2x)$
66020
What is $\mathbb Z[[t]]$? What are the double brackets?
120594
$\mathbb Z[i]/ \langle 1+2i \rangle \cong \mathbb Z_5$
109596
Isomorphism from $\mathrm{Aut}(\mathbb{Z}/2\mathbb{Z}\times \mathbb{Z}/2\mathbb{Z})$ to $S_3$
127978
Another point of view that $\mathbb{Z}/m\mathbb{Z} \times\mathbb{Z}/n\mathbb{Z}$ is cyclic.
23879
If $m$ and $n$ are distinct positive integers, then $m\mathbb{Z}$ is not ring-isomorphic to $n\mathbb{Z}$
92211
When are $\mathbb Z_m$ and $\mathbb Z_n$ homomorphic?
59533
If $\gcd(m,n)=1$, then $\mathbb{Z}_n \times \mathbb{Z}_m$ is cyclic.
46687
Elements of $GL_{2}(\mathbb{Z})$ of finite order
8434
Order of $\mathbb{Z}[i]/(1+i)$
42213
Computing $\text{Gal}(\mathbb{Q}^{ab}/\mathbb{Q})$
3203
Quotient group $\mathbb Z^n/\ \text{im}(A)$
4648
Proving that $\mathbb{Z}_m\oplus \mathbb{Z}_n \cong \mathbb{Z}_d\oplus \mathbb{Z}_l $ as groups, where $l=\mathrm{lcm}(m,n)$ and $d=\gcd(m,n)$
123482
How to compute $\mathbb{Z}_n^*$, the unit group of the integers modulo $n$?
41035
Mapping that proves $\mathbb{Z} \subset \mathbb{Q}$
77620
Irreducible polynomials over $\mathbb Q$ and $\mathbb Z $