# The Flying Colours Maths Blog: Latest posts

## A neat number trick: digital roots and modulo-9 arithmetic

This post is inspired by a question asked by Dan - thank you, Dan! So here's the gist of Dan's question: Take a random sum, e.g. 496866 + 446221 = 943087. Add up all the digits in each number (39, 19 and 31). Keep adding up the digits in each

## Secrets of the Mathematical Ninja: Sines and cosines near 45º

This is the one area where I'm better with degrees than with radians - and I suspect that's only because I don't particularly notice when radian angles are close to $\frac{\pi}{4}$, but I do when degree angles are close to 45º. This one's a trickier one than we've been looking

## Free for all Friday

June already? That sounds like it's almost summer. However, bad luck, you still have a few weeks of exams to go. How are they coming along? Well, what can I help you with this week? Just drop me a comment below and I'll do what I can to answer it.

"The race that does not value trained intelligence is doomed." - A.N. Whitehead

## Football, frustration and maths

One of my students scoffed at me the other day for saying I liked football. In particular, I like bad football - the last game I went to see was Maidenhead United against Truro City in the second qualifying round of the FA Cup, and even that was a bit

## Secrets of the Mathematical Ninja: Trigonometry With Small Numbers

Radians - as I've ranted before - are the most natural way to express angles and do trigonometry. No ifs, no buts, degrees are an inherently inferior measure and the sooner they're abolished, the better. (In other news, the campaign to replace the mishmash of units called 'time' by UNIX

## Free for all Friday

Welcome to exam season. What's on your mind? Well, what can I help you with this week? Just drop me a comment below and I'll do what I can to answer it.

## Quotable maths – Dylan

Happy Bobmas, everybody!

## The Most Massive Myth that Messes With Maths Mastery

"That's the nice thing about maths," said someone who shall remain nameless. "There's always one right answer!" I coughed. I may have said 'bullshit' under my breath, a little bit. It's my second-least-favourite thing to hear anyone say1 . The idea of maths problems always having one right answer is

## The Secrets of the Mathematical Ninja: The World's Third Most Famous Triangle

My favourite trick, when I was helping students at the Physics Homework Centre at Montana State University, was to eyeball a question for a moment and say "... which is, what, 53.13 degrees or so..." without batting an eyelid. The poor students! There they were trying to figure out which

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##### 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.