You may also like

problem icon


The nth term of a sequence is given by the formula n^3 + 11n . Find the first four terms of the sequence given by this formula and the first term of the sequence which is bigger than one million. Prove that all terms of the sequence are divisible by 6.

problem icon

Modular Knights

Try to move the knight to visit each square once and return to the starting point on this unusual chessboard.

problem icon

Divisibility Tests

This article takes the reader through divisibility tests and how they work. An article to read with pencil and paper to hand.

Old Nuts

Stage: 5 Challenge Level: Challenge Level:1

This can be solved by just working systematically with the information, thinking about which numbers are divisible by 4 and 3, and testing the possibilities.


Modulus arithmetic also provides an efficient way to solve the problem.