Divisibility

problem
Favourite

LCM Sudoku

Age

14 to 16

Challenge level

Here is a Sudoku with a difference! Use information about lowest common multiples to help you solve it.
article
The Chinese Remainder Theorem

In this article we shall consider how to solve problems such as "Find all integers that leave a remainder of 1 when divided by 2, 3, and 5."
problem

Obviously?

Age

14 to 18

Challenge level

Find the values of n for which 1^n + 8^n - 3^n - 6^n is divisible by 6.
article
Public Key Cryptography

An introduction to coding and decoding messages and the maths behind how to secretly share information.
problem
Favourite

Prime AP

Age

16 to 18

Challenge level

What can you say about the common difference of an AP where every term is prime?
problem

Dirisibly Yours

Age

16 to 18

Challenge level

Find and explain a short and neat proof that 5^(2n+1) + 11^(2n+1) + 17^(2n+1) is divisible by 33 for every non negative integer n.