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We talk to world-leading climate scientists Tim Palmer about climate and weather, the science of uncertainty, and why there needs to be a CERN for climate change.

Count down to Christmas with maths!

Where do the magnetic fields of planets and stars come from?

- In this podcast Paul Shepherd tells us about the maths of football stadiums and why his work required him to listen to Belgian techno.
Amidst all the controversy of the FIFA World Cup 2022 there is also some football to be played. And where there's football, there's maths...

I viewed Tony Sale's page to try to understand the math behind 150 million million permutations for the plugboard. His math was far too advanced for me, so I tried to approach it from a practical point of view.

With the first cord, I have 26 letters to choose from for one end, then (since a letter can't be plugged into itself) I have 25 letters to choose from for the other end. Since a letter can only be plugged into 1 other letter, that leaves 24 letters to choose from for the next cord.

Factoring 26 X 25 X 24 X ... X 7, my calculator showed the answer of approx. 5.6e23 or 56 thousand million million million, a number that's over 3.6 trillion times greater than the number that is reported in this article.

Is my calculator wrong or did Mr. Sale make a mistake? I genuinely would like to know, because I don't understand it.