It's not just 30-60 and 45-45 right-angled triangles that are special! What about a 15-75 right-angled triangle?

Solution revealed: 28 May 2021

Your challenge is to determine four prime factors of a very large number using just pencil and paper methods.

Solution revealed: 21 May 2021

Can Freddy visit every square on the chessboard?

Solution revealed: 14 May 2021

What is the probability that the eggs and eggcups match?

Solution has been revealed

What is the minimum difference between powers of these squares?

What are the least possible values for these expressions?

Three equations and four unknowns... Can you find the full set of solutions?

What kind of quadrilateral do we have here? Prove it!

Dr Reasoner has been busy again - this problem is an interesting mix of algebra and number! Can this expression take an integer value?