Finding divisibility rules
59135
What is the proof of divisibility by $13$?
14693
$d = \gcd(c,m),\ ac≡bc\pmod{\! m}\Rightarrow a≡b\pmod {\!m/d}\ $ [Congruence Cancellation & Division Rule]
14270
Polynomial divisibility is unchanged by coeff. field extension
124295
Divison and remainder in Prolog
132605
Finding the number of subsets of a set such that an element divides the succeeding element.
108275
How do I count the subsets of a set whose number of elements is divisible by 3? 4?
67104
Find maximum divisors of a number in range
56512
Divisibility is transitive: $\ a\mid b\mid c\,\Rightarrow\ a\mid c$
40538
On determinants and common divisors
82075
Understanding the trial division primality test
139776
Divisibility tests and remainder mod $9,11,99,101,999,1001\,$ (casting out nines and elevens)
108919
Numbers till 400 divisible by 2, 3, 5, 7
134921
Find the number of all subsets of $\{1, 2, \ldots,2015\}$ with $n$ elements such that the sum of the elements in the subset is divisible by 5
117761
When is $\binom{n}{k}$ divisible by $n$?
15452
Proving determinant product rule combinatorially
74523
Proof by Cases involving divisibility
39969
Algorithms for computing multiplicative order modulo $n$