*Double Maths First Thing is Colin’s weekly assortment of mathematical news. Or what time’s manacle.*

Hello! My name is Colin and I am a mathematician on a mission to spread joy and delight through the medium of mathematics. It’s Wednesday morning and it’s time for Double Maths First Thing.

## On magic

It’s probably a bit gauche to start with an article I wrote, but it’s certainly something that caught my eye: Rob Eastaway (all-round good egg and author of Much Ado About Numbers, available wherever good books are made available) sent me a page from the diary of an Elizabethan impresario describing a card trick. Here’s my description of how it works — with a bit of help from young Bill.

A different kind of magic goes on under the bonnet of your average computer. (Computers should definitely have bonnets. “Oooths, looks like your fan belt’s gone, that’s going to be expensive.”) When you input a number, the computer takes it in as a string of characters. How does that get turned into an Actual Number? It’s surprisingly complicated.

## On beauty

You say you have found beauty

In Euler’s identity

It’s basic trigonometry

It’s Pi Day, I’m in a huff

Even when it’s *not* Pi Day, I get in a huff about the framing of Euler’s identity as “the most beautiful equation”. Andrew Stacey articulates it a lot more clearly than I would, and with less swearing.

I’ll accept that dance can be beautiful (I have a cousin who’s a professional choreographer, and who has a very stern Disapproving Look, so I have to say that). Here’s a nice piece about different styles of dance notation; my only criticism is that they don’t make a joke about Scottish country dancing needing a Ceilidh table.

## On stupidity and getting things wrong

Another article that’s had me nodding along and saying “YES!” is this from Math For Love: it makes the powerful point that *feeling* stupid is an important part of becoming smarter — and it’s an entirely different thing from *being* stupid.

One thing that always makes me feel stupid is how our experience of the world is pretty much limited to an incredibly narrow shell — a plane at 30,000 feet is 0.14% of an Earth radius up in the air. It turns out that GPS and route-trackers generally are just… not very good at elevation.

This also prompted me to look up: the Earth is neither smoother nor rounder than a billiard ball, but it’s pretty close.

## On my way out

A couple of final things: I recently stumbled on Cyrille Rossant’s Awesome Maths List — I’m sure some of you know of resources that belong on there, and he seems receptive to pull requests.

I’ll end with something *else* about me: this year, I’m doing something I’ve never done before. I’m going into my kids’ school to run a lunchtime code-breaking club around the National Cipher Challenge for years 5 and 6. (The headteacher almost bit my hand off, it sounds like they’re studying Bletchley Park this term). I’ve done the challenge before, it’s just the wrangling young’uns that’s new.

In the meantime, if you have friends and/or colleagues who would enjoy Double Maths First Thing, do send them the link to sign up — they’ll be very welcome here.

If you’ve missed the previous issues of DMFT or — somehow — this one, you can find the archive courtesy of my dear friends at the Aperiodical.

That’s all for this week! If there’s something I should know about, you can find me on Mathstodon as @icecolbeveridge, or at my personal website. You can also just reply to this email if there’s something I should be aware of.

Until next time,

C