$(\Bbb Z[x]/(x^{n+1}))^\times\cong\Bbb Z/2\Bbb Z \times \prod _{i=1}^n \Bbb Z$
118299
Show that $(\mathbb{Z}[x]/(x^{n+1}))^{\times}\cong \mathbb{Z}/2\mathbb{Z}\times\Pi_{i=1}^n\mathbb{Z}$
61666
Proving $ [(\vec{a}+\vec{b})\times(\vec{b}+\vec{c})]\cdot(\vec{c}+\vec{a})=2\vec{c}\cdot(\vec{b}\times\vec{a})$
156910
Necessary and sufficient condition for $R/IJ \cong R/I \times R/J$
87289
Find the multiplicative inverses of all the elements in $\Bbb Z_{16}^\times$
150166
What is $P([a_1,b_1]\times [a_2,b_2]\times...\times[a_k,b_k])$
139833
Prove that $\gcd(M, N)\times \mbox{lcm}(M, N) = M \times N$.
133915
In which case $M_1 \times N \cong M_2 \times N \Rightarrow M_1 \cong M_2$ is true?
66313
$\mathbb{Z}[i]/(a+bi) \cong \mathbb{Z}_{a^2+b^2}$ if $(a,b)=1$
47522
group generators of $(\mathbb Z_{17}-\{0\},\times)$
122312
How can I compute $\mathrm{Aut}(\mathbb{Z}/4\mathbb{Z}\times\mathbb{Z}/6\mathbb{Z})$?
129827
Product of invertibles in $\Bbb Z_n$ [Wilson's Theorem generalization]
39231
Construct a bijection between $\mathbb{Z}^+\times \mathbb{Z}^+$ and $\mathbb{Z}^+$
55393
Existence of a group isomorphism between $(\mathbb K,+)$ and $(\mathbb K^\times,\cdot)$
102175
$Z=XY$, $E_Z[Z]$, $E_{X,Y}[XY]$
154698
Union of Cartesian products: $X \times (Y \cup Z)= (X \times Y) \cup(X\times Z)$
132311
T$\mathbb{S}^{n} \times \mathbb{R}$ is diffeomorphic to $\mathbb{S}^{n}\times \mathbb{R}^{n+1}$
58033
$G\times H\cong G$ with $H$ non-trivial