Browsing category basic maths skills

Exchange rates on board

“Three teas, please,” said the passenger ahead of me in the queue. The Armorique was due in Plymouth any minute, and tea was of the essence. “That’s £4.65, or €5.601.” Hang on a moment, I thought, remembering to order my own tea as well. 560 isn’t a multiple of 3.

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On $0 \div 0$

A question that frequently comes up in the insalubrious sort of place a mathematician might hang around is, what is that value of $0^0$. We generally sigh and answer that the same way every time. It was nice, then, to see someone ask a more fundamental one: what is $0

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The Maths Behind… Cakes

“Cooking,” said my friend Liz in a recent Facebook post, “is one of the activities where maths is most useful in my everyday life.” She added this picture: I’ve got several reasons for wanting to share this. 1. It’s pretty much a model answer Imagine you’re in a GCSE exam,

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How the Mathematical Pirate works out the high times tables

“Arr!” said the Mathematical Pirate. “Pieces of eight!” said the Mathematical Pirate’s parrot. “How many pieces of eight?” “Seven!” “That’ll be… seventy and ten minus twenty and four, making fifty and six!” “Who’s a clever boy?” asked the parrot. “Awk!” — The Mathematical Pirate is, indeed, a clever boy. He’s

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The times table game

Every Friday afternoon, double maths with Mr Hutt: he would march up and down the classroom, barking: “Number seven: six times eight. Six times eight. Number eight: …” Twenty times tables questions, rapid-fire, scores kept. (One week, I fumbled $7\times 8$, blemishing my perfect score; Paul Edwards, on the other

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Ask Uncle Colin: These percentages don’t add up!

Dear Uncle Colin, I’m a bit confused! Someone told me that 40% of all Americans on welfare are black, which means that 66% of black Americans are on welfare. How did they work this out? I don’t get it, and it’s bothering me. — Always Back Equality Legistlation Hi, ABEL!

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Ask Uncle Colin: These alcohol-related figures look a bit fuzzy

Dear Uncle Colin, I was recently on a tour of a whisky distillery where the guide told us about the ‘angel’s share’: every year, 2% of the alcohol in a bottle evaporates. He went on to explain that a 25-year-old single malt would have half the alcohol it did originally.

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$6\times4$ or $4\times6$?

Every so often, a question that comes up that looks incredibly trivial, but – no matter how much each side protests that the preference doesn’t really matter – sets down clear divides in the maths community. My podcasting partner in crime-fighting @reflectivemaths (Dave Gale in real life) stumble upon such

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Why $17 \times 24$ isn’t 568

“You would not be certain that $17 \times 24$ is not 568.” – Daniel Kahneman, Thinking Fast And Slow Thanks to Alice for pointing out that yes, she bloody well would. Most people under 50 in the UK would reach for a calculator, or possibly a pen and paper to

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TMTOWTDI: Subtraction

“There’s more than one way to do it.” – Perl programming motto One of my few regrets about writing maths books is that I usually only get to show one way of doing things – and that gives the impression that I believe Method X is absolutely, no questions, the

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