Newsletter

Teaching the Wrong Class

Wednesday 1st January 2025

This is the Transum Newsletter for the month of January 2025.

Happy New Year - It's great to be alive
Now we have started twenty, twenty-five
A number that's special, a number that's fine
It's the sum of the cubes from one to nine*.

And to begin the year, here is the puzzle of the month.

It’s the end of the morning break at Addwell School, and ten classrooms, packed with enthusiastic students, are waiting for their next lesson to begin.

Ten teachers leave the staffroom one by one after consuming their morning coffee. The first to leave is Professor Hamnee Shah, who can’t remember which class he is timetabled to teach, so he chooses a class at random and begins teaching them.

The second teacher does the following: goes to their timetabled classroom. If there is no teacher inside, they teach their scheduled class. Otherwise, they choose a random class with no teacher and begin teaching. Every one of the remaining eight teachers does the same. What is the probability that the last teacher out of the staffroom (Ms Lattelike) teaches their timetabled class?

If you get an answer, I'd love to hear how you solved the puzzle (or your students solved it). Drop me an email at: gro.musnarT@rettelsweN

As I mentioned this time last year, I am the honorary Chair of British Scouting Overseas, Rest of the World District. Each year I set a Christmas Challenge. I guess you have a few days of the festive holiday left, so I wonder if you can do the Camp Bosrow Challenge?

And now for something completely different. Sorting Shapes exists to fill a gap in the Functional Skills offerings. There are four levels involving both two-dimensional and three-dimensional shapes. The challenge is enhanced with the fact that no mistakes are tolerated (that sounds a bit harsh). If a mistake is made you'll need to start that level again. Hopefully it will keep pupils focused and add to the sense of achievement when the level is completed.

During December, I returned to the UK to see my 92-year-old mother and the rest of the family. Mum enjoys watching the TV programme The 1% Club, so I watched a number of episodes with her while I was at her house.

Many of the questions are very similar to Transum starters and puzzles, and I’d like to think that the show’s researchers may have stumbled upon Transum while searching for question ideas. All of the questions used have been tested on members of the general public prior to the show, and are classified according to the percentage of participants who answered correctly.

Here is the big finale question from the last programme I watched. It’s the question that only 1% of the public got right:

In a room of 100 people, 99% are left-handed. How many left-handed people have to leave the room to bring that percentage down to 98%?

So if the Puzzle of the Month didn’t catch your interest, you may wish to give this conundrum some thought. Pause your reading and ponder!

These GCSE Question Collections were originally designed to be printed on paper, with each question automatically printed on a separate page. Now, I print to PDF and import it into BitPaper. Save the planet while revising!

Talking of exams, I heard that the Suneung, South Korea's gruelling university entrance exam, is an eight-hour marathon held on a single day, making it one of the toughest exams in the world. Unlike the UK, where exams are spread over weeks, Korean students face back-to-back tests with minimal breaks. The exam's significance is so immense that the entire country comes to a standstill; stock markets adjust their opening hours, and flights are grounded to ensure students can focus. This life-defining exam determines university admission, career prospects, and even relationships, reflecting the intense societal pressure around it. I found out about the Suneung from a BBC podcast called What in the World; heartily recommended.

Don't forget you can listen to this month's podcast, which is the audio version of this newsletter. You can find it on your favourite podcast catcher. It's called Transum Mathematics Puzzles.

Finally, the answer to last month's puzzle which was:

While Santa was busy delivering presents in Tran Towers, Prancer, one of his reindeer, went for a stroll to the base of Krimble Hill. Prancer then walked up the hill to see the view of Twinkle Town from the top. After enjoying the view, Prancer retraced his steps back to the Towers. His round trip took six hours. Prancer walked at an average of 4 km/h on level ground, 3 km/h uphill, and 6 km/h downhill. How far (in km) did Prancer walk?

The answer is 24km. This problem was adapted from a question in the 1991 UKMT Senior Mathematical Challenge.

The first five people to send in a correct solution were Kevin, Mala, Dalia, Tzvetanka and Beth. I have enjoyed receiving the emails from all those who took part. It is fascinating to see the wide variety of methods employed to solve the same puzzle and some examples can be found below.

That's all for now,

John

P.S. Why is a dog with a bad foot like adding 6 and 7?

A. Because he puts down three and carries the one.

* 2025 is also the square of the sum of the numbers one to nine.

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