Take a look at the multiplication square. The first eleven triangle numbers have been identified. Can you see a pattern? Does the pattern continue?
Delight your friends with this cunning trick! Can you explain how it works?
Can you describe this route to infinity? Where will the arrows take you next?
Where we follow twizzles to places that no number has been before.
Arrow arithmetic, but with a twist.
A loopy exploration of z^2+1=0 (z squared plus one) with an eye on winding numbers. Try not to get dizzy!
Make the twizzle twist on its spot and so work out the hidden link.
We've received a clear solution to this problem from Alice, George, Kyle, Tom, Nell and Alex.
Go to last month's problems to see more solutions.
Infinity is not a number, and trying to treat it as one tends to be a pretty bad idea. At best you're likely to come away with a headache, at worse the firm belief that 1 = 0. This article discusses the different types of infinity.
This Sudoku puzzle can be solved with the help of small clue-numbers on the border lines between pairs of neighbouring squares of the grid.