And, what I'm gonna show you today is that there are good ways and there are bad ways of cutting a cake.

And the classic way, the bad way, is like this, which will be normal.

You put the knife in the center, one bit of a slice, a bit of a slice.

That's not the classic.

It is the classic, isn't it? It's almost like a pie chart.

You know one thing about the word pie chart, in France,

they call them, Camembert, which is like a cheese.

It actually got a cheese chart in France.

Interesting cultural differences. enough speak

So, this is what you'll do, you take this, you'd put this over here.

You eat it, and you leave this in the fridge overnight.

And the reason why this is a really bad way of cutting a cake,

is that these bits here are just going to get dry.

And so when you come the following day to have your cake,

you do another one, another slice like this,

This side here, lovely and soft. This will be dry and horrible.

You know, maximizing the amount of gastronomic pleasure that you can make from this cake

there is a better way. A way that is more than a hundred years old,

and was discovered or invented by one of Britain's most famous and brilliant mathematical scientists.

This is a copy of Nature, the famous science magazine from December 20th, 1906.

In the letters to the editor here it says, headline, Cutting a Round Cake on Scientific Principles

The ordinary method of cutting out the wedge is very faulty

What he suggests is, and he gave a illustration for it,

tha proper way, the scientific way, the mathematically perfect way of cutting a round cake, and it is as follows.

So, we have another cake. The first slice will be like this.

It's breaking all the rules of a cake etiquette. Perfect. Okay. So, this is the first one.

And then I need to find a way of taking it out. We can set that there.

That's gotta be the prime steak of that cake, isn't it? It's the t-bone cut.

Here we need to do, we need to close the cake together like this, and it's gonna come apart.

So look what I got here, I have got some rubber bands to make sure it stays together.

The following day, all the flesh, the sponge is going to be nice and soft.

So, how do they do the second slice? The second slice, because it's not your birthday anymore,

so you're not gonna have this slice quite as big. Interesting to work out that actual proportion.

This is, and you got a lovely break into the elastic band too. it's exciting

This is slice two, or it actually is slice two which has two slices, two parts.

Good. So you put this back together. And we can keep on going,

Obviously again I want to use the elastic band to put the cake together.

That is perfect. That's gonna stay so fresh for day 3. Day 3, how should we do day 3 again?

Let's, um, turn it around. I think this is gonna be the slice for day 3.

Again, the satisfying snap of the elastic band.

I don't know if you thought of them before, but this triangular slices are really annoying anyway because it's not very satisfying.

Having a nice uniform slice like that is a lot better.

So, here we go again, it's the end of day 3.

And this is gonna be perfect, and gradually, we are slicing it. Keep on going.

I think for the, um, mathematical loners, who don't want to share their cake, it can be useful.

For a bit more interview including more about the guy who came up with this cake cutting method, have a look of the extra footage over on Numberphile2.

And if you just like to hear more great stories from Alex, he's got a new book out just recently,

Alex Through the Looking Glass, How Life Reflect Numbers and Numbers Reflect Life

It's really good, it's also just out in the US, but it has a different name in the US.

It's called, The Grapes of Math. I will put links to it in the video description.