Posted in ninja maths, radians.

I'll hold up my hands here and say: most of the secrets of the mathematical ninja are guides to showing off. Few of them have much practical use beyond making everyone else in the class look at you funny. This one - converting degrees into radians - is different. If

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Posted in logarithms, ninja maths.

You might think 'when would I ever write to an abstract concept like logarithms', but you'd be surprised. I had occasion to write this letter a few weeks ago: Dear Base 10 Logarithms, I'm very sorry that I bullied you. I recall saying things like 'grown-ups always use natural logs',

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Posted in ninja maths.

Countdown puzzle: Make 952 from 100, 75, 50, 25, 6 and 3 Have a go at this one before you read on. It's pretty straightforward to make 953 (exactly as the poor antagonist, Gerald, in this story does): 100 × (6 + 3) = 900 900 + 50 = 950

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Posted in ninja maths.

Countdown puzzle: Make 952 from 100, 75, 50, 25, 6 and 3 Have a go at this one before you read on. It's pretty straightforward to make 953 (exactly as the poor antagonist, Gerald, in this story does): 100 × (6 + 3) = 900 900 + 50 = 950

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Posted in ninja maths.

Countdown puzzle: Make 952 from 100, 75, 50, 25, 6 and 3 Have a go at this one before you read on. It's pretty straightforward to make 953 (exactly as the poor antagonist, Gerald, in this story does): 100 × (6 + 3) = 900 900 + 50 = 950

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Posted in ninja maths, probability.

Million-to-one shots come up nine times out of ten. - Terry Pratchett While researching rules for ninjas to live by (don't ask), I came across a mathematical phenomenon I'd never noticed noticing. It's this: The Law of Inverse Ninjas: The probability of a group of ninjas winning a battle in

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Posted in ninja maths.

Your average ninja (if there is such a thing) doesn't need to do the swirly-sword manoeuvre. If he wanted, he could just run you through and you'd be dead before you even noticed he was there. But that's rather rude and unsophisticated, the kind of thing a pirate might do.

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Posted in ninja maths.

Learning the rough value of a few key numbers worth knowing can make ninja maths a lot more impressive later on - especially if you know how roughly how rough the rough values are. A little bit about the tables below: I'm giving you decimals to two sig figs, the

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Posted in ninja maths.

Difficulty: ** Impressiveness: **** If you do A-level maths, you do an awful lot of integration. You integrate polynomials, trig functions, partial fractions, exponentials, parametric curves, products of these... and get nice analytical answers. Here, let me provoke controversy: Unless you're going to be a pure mathematician or a maths

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Posted in ninja maths.

Difficulty: (simple version) *** (advanced version) ***** Impressiveness: ***** Accuracy: *** If you're a statistician, you quite often end up working out powers of numbers just a little less than 1. What's the probability of rolling a pair of dice ten times and never getting a double six? It's $\left(\frac{35}{36}\right)^{10}$.

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