Mathematics Pizza & Pi

Chris Hobson

Well-Known Member
Relationship to Diabetes
Type 2
I came across this story on the not always right website and it made me brush off my very rusty school maths skills:

, 2020
The missus and I get a bit of a hankering for a pizza so I give our local pizzeria a call and order an 18” meat feast for collection.
A short while later, I stroll down to the shop to collect it. While I am waiting for it to be boxed up, a woman comes bustling in and raps her knuckles imperiously on the counter demanding service; the only person serving was currently out the back dealing with my order.
The lass dutifully comes out, tells me that my pizza will be out shortly, and turns to the woman to take her order.
Customer:
“I want two 12” meatball specials and be quick about it: I have two hungry kids at home!”
Me: “Excuse me, but if both pizzas are for your family, you’re better off getting one 18” pizza: it’s cheaper and you’ll get more pizza for your money.”
A 12” is £8.95: an 18” is £12.50.
Customer:
*looks me up and down* “Don’t be stupid! Two 12” pizzas are more than one 18” one. It’s bloody obvious! Didn’t you do maths at school?”
Me: “I did… which is why I know one 18” pizza is bigger than two 12” ones by about 10%.”
She snorts derisively and turns to the lass serving.
Customer:
“I’ll be back in twenty minutes… and my pizzas had better be ready!”
With that, she sweeps out in a cloud of cheap perfume. I look over to the lass serving who could barely contain her laughter:
Me: “We get this all the time. Doesn’t matter what you say, people never believe that the 18” is a better deal than two 12” ones. They always think we’re trying to rip them off.”
This is why you pay attention in maths class. The pizza was delicious!

As I recall, the formula for calculating the area of a pizza is A=Pi times radius squared. That had to be written in a slightly long winded way as I can't find the necessary mathematical symbols on my phone. Anyway, the area of a 12" pizza works out at 112.4 square inches and the area of the 18" pizza works out at 254.5. This means that the two smaller pizzas have a combined area of only 224.8 and are indeed smaller.
 

mikeyB

Well-Known Member
Relationship to Diabetes
Type 1
I make my own pizzas from scratch. Mix the dough (70% 00 flour, 30% fine ground semolina to 200g) olive oil, 7g sachet of dry yeast, salt and water) . These days I use the Kenwood to do the kneading. Then stick the dough in warm place - my oven has a dough proving setting.

While the dough is rising, make the tomato topping. 1 tin chopped tomatoes, 2 tablespoons of tomato purée, and dried oregano. Then prepare your toppings of choice.

For cooking I use a pizza stone (around £20 from Amazon or other reliable supplier). I stick that in the oven at 200 degrees at least 15 minutes before putting the pizza on it with a pizza paddle - like a wooden shovel, also cheap. That way, you get a really crisp bottom that you can never get in a take-away. Takes around 10 minutes to cook. One tip - flatten out the dough on a piece of non-stick baking paper cut to the size of the pizza stone, then slide the paddle underneath the paper to put it on the fiercely hot pizza stone, and take the pizza off the same way. Unless you fancy a visit to A&E don’t touch the pizza stone, and let it cool in the oven. Don’t stick the stone in cold water in the sink to cool it down, it will shatter.

From beginning to end, the fastest I’ve done that is an hour and a half. The kit you need for the cooking stage is the best investment you’ll make. When did you last fancy a pizza to order one that takes about as long as to arrive, soggy, chewy and damp?

The oven and the Kenwood comes in around £1500, mind.
 

Chris Hobson

Well-Known Member
Relationship to Diabetes
Type 2
I noticed that the last quote in the original story should have been from the person in the shop, I suspect that the person who wrote it made a slight error.

Mikey you must really love pizza to go to that much trouble. I do like to cook things from scratch sometimes, it is rarely any cheaper but if you get it right you can get a better result. I like curry but I generally make it with sauce from a jar. Nobody else in my house likes it and it doesn't seem worth the effort to learn how to make it just for myself. Chocolate brownies are the thing that I'm making at present, they disappear pretty quickly so I must be doing something right.
 

mikeyB

Well-Known Member
Relationship to Diabetes
Type 1
I’m not a pizza addict, but I can’t go and collect an ordered pizza any more than fly. And my pizzas come out at around £3, all in. Much better quality, too. It’s no real effort (I’m sitting on adjustable height stool for most of the job). It’s a pleasure to do it, a job done well.
 

Chris Hobson

Well-Known Member
Relationship to Diabetes
Type 2
Of course the OP was more about the counter intuitive nature of mathematics than about pizza. About 99% of the maths that I learned at school is stuff that I have never used once I passed my exams. Equations that use pi are an exception and pythagoras theorem has proved useful from time to time. I have done night classes on electronics which required knowledge of basic algebra. Despite being good at maths and certainly above average intelligence, In my younger days I was pretty inept at handling money. Meaning that, despite earning a decent amount, I was often skint. Yes I eventually got my act together but how much better would it have been if school maths had been about money management and interest rates rather than quadratic equations?
 

Minky

Member
Relationship to Diabetes
Type 2
Seem to remember New Maths didn’t have much about money management. The Old Maths had a bit more about working out percentages. Hence my husband, a year ahead of me in school years, learned to count and estimate. Me on the New Maths, know ‘all shends are umpty’, but that hasn’t helped when working out wallpaper drops or mortgage rates.
Kudos to those that know the phrase from Venn diagrams.
 

SB2015

Forum Host
Relationship to Diabetes
Type 1
This thread caught my eye when catching up on the forum.

Sounds like another good excuse for a practical maths lesson.
Week 1
Measure BG of all students before lesson. Find total
Share out 2 12” pizzas, wait one hour, measure BGs find new total.
Week 2 repeat with 18” pizza.

Or ....... just do the calculations!!
 
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