Take a look at the video and try to find a sequence of moves that will take you back to zero.
It would be nice to have a strategy for disentangling any tangled
Look carefully at the video of a tangle and explain what's
Can you tangle yourself up and reach any fraction?
An aluminium can contains 330 ml of cola. If the can's diameter is 6 cm what is the can's height?
A ribbon is nailed down with a small amount of slack. What is the
largest cube that can pass under the ribbon ?
Your school has been left a million pounds in the will of an ex-
pupil. What model of investment and spending would you use in order
to ensure the best return on the money?
A fire-fighter needs to fill a bucket of water from the river and
take it to a fire. What is the best point on the river bank for the
fire-fighter to fill the bucket ?.
When is a knot invertible ?
A plastic funnel is used to pour liquids through narrow apertures.
What shape funnel would use the least amount of plastic to
manufacture for any specific volume ?
We received several good solutions to this problem.
Go to last month's problems to see more solutions.
A personal investigation of Conway's Rational Tangles. What were
the interesting questions that needed to be asked, and where did
A pair of Sudokus with lots in common. In fact they are the same problem but rearranged. Can you find how they relate to solve them both?
Help the bee to build a stack of blocks far enough to save his
friend trapped in the tower.