Any number coprime with 10 dividing at leat one number of the form 111...111
113531
Repunit Divisibility
29099
Let consider a square $10$x$10$ and write in the every unit square the numbers from $1$ to $100$
72406
Last two digits of $2^{1000}$ via Chinese Remainder Theorem?
129492
Choosing $15$ out of $100$ whole numbers with difference of any $2$ divisible by $7$
28496
Generating the partitions of a number
147485
A conjecture about numbers of the form $10^{m}(2^{k}−1)+2^{k-1}−1$, where $m$ is the number of decimal digits of $ 2^{k-1}$.
64985
Get the numbers from (0-30) by using the number $2$ four times
23818
Divisibility Rules for Bases other than $10$
156577
The cube of any number not a multiple of $7$, will equal one more or one less than a multiple of $7$
25320
Convert any number to corresponding word
120822
A 10x10 table filled with 0 to 9 numbers
139350
Given two coprime integers, find multiples of them that differ by 1
48908
Choose 100 numbers from 1~200 (one less than 16) - prove one is divisible by another!
140144
Can you find an element of order 10 in $\mathbb{Z}_{31}^{*}$
109055
Round number up to the nearest multiple of 3
73206
recursion-consecutive numbers
94983
Can an odd number $n$ divide $2^n-1$?