Additive group of $\mathbb{Z}[x]$, ring of polynomials over integers.
93169
Show that $(\mathbb Z[x],+)$ and $(\mathbb Q_{>0},\cdot)$ are isomorphic groups
148550
Units in quotient ring of $\mathbb Z[X]$
143069
What are the direct summands in $\mathbb{Z}^n$?
5996
Are $(\mathbb{R},+)$ and $(\mathbb{C},+)$ isomorphic as additive groups?
8434
Order of $\mathbb{Z}[i]/(1+i)$
157488
Proving that $k[x,y,z]/(xz - (y^2 + 1))$ is a normal ring.
88307
Commutative property of ring addition
622
Galois Group of $\sqrt{2+\sqrt{2}}$ over $\mathbb{Q}$
124864
A not free $\mathbb{Z}$-module
87617
Ring of $\mathbb{Z}_2$-valued functions
140557
Counting ring homomorphisms from $\mathbb{Z}[x,y]/(x^3+y^2-1)$ to $\mathbb{Z_7}$
87946
Proving that the unities of a ring form a group under multiplication
93703
Groups of units of $\mathbb{Z}\left[\frac{1+\sqrt{-3}}{2}\right]$
119297
Finding invertible polynomials in polynomial ring $\mathbb{Z}_{n}[x]$
21840
Zero divisors and units for the ring $\mathbb{Z}/n\mathbb{Z}$ with integer $n$
30753
Showing there is no ring whose additive group is isomorphic to $\mathbb{Q}/\mathbb{Z}$
77903
Finding the integral closure of $\mathbb{Z}$ in $\mathbb{Q}[i]$