Bobby Seagull: Strictly Come Dancing is a Maths Show

Strictly Come Dancing is not a ballroom dancing show or even a celebrity popularity contest – it’s a maths show!

The reason it is still the biggest name in Saturday night TV comes down to one number in particular – the huge viewing figures.

But the entire contest is shot through with mathematics.

At its most basic level it’s about counting. The contestants have to keep to the beat and that means counting in time to the music. You’ll often see the professionals yelling at their celebrity partner throughout a routine, they aren’t just offering encouragement, usually they are saying the same thing over and over – ‘one, two, three, four’ to keep in time.

And the numbers get more complex. Some dances require half or quarter beats so everyone involved needs an understanding of what is a fraction.

And that’s before you even get into the more complex maths in music such as frequency and symmetry and the fact that music that follows certain mathematical rules tends to be more popular and more touching.

It’s why my friend Katya Jones and I often work together on maths videos. Katya is famous for coming up with awe inspiring dance routines but she understands that her most famous moments – from jumping out of a dustbin with Tony Adams to that Gangnam Style routine with Ed Balls – would not be so spectacular without the mathematics that underpins music and dancing.

There is of course another mathematical aspect to Strictly. Each week the judges award the routines marks out of 10. Because we work tend to work in a base 10 system of numbers. In other countries or in other times in history the judges might give marks out of 12 or 20 or 60.

And each week another couple falls foul of the dreaded dance off and leaves the competition.

To determine who stays and who does not each week the judges scores are added to the public vote. But in order to ensure that both the judges’ verdicts and the public’s choices are given roughly equal weighting – ensuring that skill and popularity are both valued – the producers have had to concoct an algorithm that combines all the numbers in a way that is fair and sensible. And they’ve honed that algorithm over the course of 21 series. That’s how all maths develops and evolves – with theories and proofs perfected over time with lots of different people contributing to improving it. Just as a dance show featuring just one person would quickly grow boring so maths relies on people working together, bringing their particular skills to the table and producing something that makes the world a better and more interesting place.

I love Strictly and I love maths. I love Strictly because I love maths. It’s a perfect example of how maths is all around us, often in surprising places but, more than that, it demonstrates how maths is fundamental to things like music and entertainment – the things that make us human and make life enjoyable.

Bobby Seagull is a maths teacher, broadcaster and writer.