The Flying Colours Maths Blog: Latest posts

Ask Uncle Colin: Decimal arithmetic

Dear Uncle Colin, How do people do decimal calculations like $80 \times 0.15$ in their heads? It seems impossible. – Doesn’t Everyone Seem Clever, Answering Readily These Evil Sums Hi, DESCARTES, and thank you for your message! There are several possible strategies for a question like this – how I

Read More

The Mathematical Ninja And The Driving Awareness Course

“What are you doing here?” “Never mind that, sensei, how on earth did they catch you?” “… I don’t want to talk about it. In any case, I was only doing 5% more than the speed of light.” “Yeah, that poses more questions than it answers, in honesty.” The Powerpoint

Read More

Ask Uncle Colin: A Log Approximation

Dear Uncle Colin, According to John D Cook, you can estimate the natural logarithm of a number $x$ by working out $\log_2(x)-\log_{10}(x)$. It seems to be pretty accurate – but why? Not A Problem – Interesting Exponential Riddle Hi, Napier, and thanks for your message! That is indeed a conundrum:

Read More

On Customer Survey Forms

In the olden days, I had a proper job1 writing software for customer survey forms. Among other things, our users could ask their customers to rate how likely it was that they would recommend the product to their friends. Typically, this would be on a ten-point scale, from extremely unlikely

Read More

Ask Uncle Colin: Two triangles

Dear Uncle Colin, When I’m 8 metres away from a flagpole, the angle of elevation to its top is exactly 40º, according to this angle-measurey-majigger I have here. What will it be when I’m only five metres away? The Hypotenuse Eludes One; Does One Look Into Trigonometric Expressions? Hi, THEODOLITE,

Read More

Wrong, But Useful: Episode 59

In Episode 59 of Wrong, But Useful, we’re joined by @el_timbre, who is Emma Bell in real life. We discuss: Emma’s Roots column in Chalkdust1 Number of the podcast: 64, because it’s pleasing, and Dave sings the 64 Zoo Lane theme, which is less so. Emma’s hexastix construction and the

Read More

The Maths Behind The Errors In The Maths Behind

I recently had a flurry of correspondence with translators of The Maths Behind (available wherever etc., but also soon in Swedish and Korean): embarrassingly, they had caught several mistakes in the book. These things happen; we try to put them right and move on. However, it got me wondering: can

Read More

Ask Uncle Colin: A Trigonometric Proof

Dear Uncle Colin, I have a trig identity I can’t prove! I have to show that $\frac{\cos(x)}{1-\sin(x)} = \tan(x) + \sec(x)$. Strangely Excited Comment About Non-Euclidean Trigonometry. Hi, SECANT, and thanks for your message! This is a slightly sneaky one, but definitely a good one to practice. Let’s do it

Read More

Complex transformations (and incorrect wording?)

You know how I often bang on about how ‘impossible’ exams are really nothing of the sort? Well, just for a change, I’m going to bang on about how sometimes exam boards get it wrong. I’m looking at the 2014 Edexcel FP2 paper (the normal one, not the (R) one

Read More

Ask Uncle Colin: A Tangential Conundrum

Dear Uncle Colin, I was asked to work out $\tan\br{\theta + \piby 2}$, but the formula failed because $\tan\br{\piby 2}$ is undefined. Is there another way? – Lost Inna Mess, Infinite Trigonometry Hi, LIMIT, and thanks for your message! In fact, there are several ways to approach it! Basic geometry

Read More

Sign up for the Sum Comfort newsletter and get a free e-book of mathematical quotations.

No spam ever, obviously.

Where do you teach?

I teach in my home in Abbotsbury Road, Weymouth.

It's a 15-minute walk from Weymouth station, and it's on bus routes 3, 8 and X53. On-road parking is available nearby.

On twitter