Wrong, But Useful: Episode 68

In this month’s thrilling installment of Wrong, But Useful, we’re joined by @c_j_smith, who is Calvin Smith in real life.

We discuss…

  • Number of the Podcast: 5
  • Are Fish and Chip shop owners good at maths?
  • Two maths puns and a maths joke
  • Are there ‘popular’ books that ‘lead you in’ to mechanics?
  • An application of the sum-of-squares problem
  • Via @PaulsPrattle (Paul O’Malley): “If you were the ruler of the universe tomorrow what would be the objective in secondary mathematics learning for all kids everywhere?”
  • Via @aap03102, (Chris Smith)’s newsletter: some love for Simon Plouffe
  • Via @christianp: The Big Mathoff is running again
  • Puzzle feedback from last time: We hadn’t seen any solutions when we started recording, but some have come in since - we’ll mention those next month. However: Chris pointed out a tweet from @mathsjem (Jo Morgan) showing the clock-hands puzzle in Thompson’s Practical Algebra, published in 1878.
  • New Puzzle: There are 3 lighthouses. The first shines for 3 seconds and then is off for 3 seconds. The second shines for 4 seconds and then is off for 4 seconds. The third shines for 5 seconds and then is off for 5 seconds. Initially, all three come on together. When is the next time they’re all on at the same time?


Colin is a Weymouth maths tutor, author of several Maths For Dummies books and A-level maths guides. He started Flying Colours Maths in 2008. He lives with an espresso pot and nothing to prove.


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I teach in my home in Abbotsbury Road, Weymouth.

It's a 15-minute walk from Weymouth station, and it's on bus routes 3, 8 and X53. On-road parking is available nearby.

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