Proving $ C = D $ from $ A \triangle C = A \triangle D$
67717
$A \oplus B = A \oplus C$ imply $B = C$?
101803
A\(B∩C) = (A\B) ∪ (A\C) how to prove?
24912
Show that if $fd'=f'd $ and the pairs $f, d $ and $f',d' $ are coprime, then $f=f' $ and $d=d' $.
2208
$\gcd(a,b,c)=\gcd(\gcd(a,b),c)\,$ [GCD Associative Law]
66563
Is $ (A∪B)×(C∩D)=(A∪C)×(B∪D)$ true for all sets A,B,C and D?
157508
prove $lcm(a,gcd(b,c))=gcd(lcm(a,b),lcm(a,c))$
109318
Equivalence relation $(a,b) R (c,d) \Leftrightarrow a + d = b + c$
119156
$(a,b)=d \overset{?}{\implies} (a^3,b^3)=d^3$
111800
If $a|c$ and $b|d$, is it true that $ab|cd$?
118809
If $a$ divides $bc$ and $\gcd(a,b) = d$ then $\frac a d$ divides c
46106
Prove that $D_r \circ D_s = \{ (x,y) \in \mathbb{R}^2 \ | \ |x-y|<r+s \}$, where $D_a = \{ (x,y) \in \mathbb{R}^2\ | \ |x-y| < a \}$
157784
Prove that if $\gcd(ab,c)=1$, then $\gcd(a,c)=1$.
11216
Induction: How to prove that $ab^n+cn+d$ is divisible by $m$.
29935
If $a, b, c, d>0$ and $abcd=1$ prove that an inequality holds true
106416
If $n,m \in \mathbb{N}$ then there are $c,d$ such that $cd = (m,n)$, $(c,d) = 1$ and $(m/c,n/d) = 1$.
140440
Proving $(A\times C)\cup(B\times D)\subseteq(A\cup B)\times(C\cup D)$
116205
System of equations in a,b,c,d