Here’s our annual round-up of what’s happening in sums/thinking at this year’s Manchester Science Festival. If you’re local, or will be in the area around 20th-30th October, here’s our picks of the finest number-based shows, talks and events.

# You're reading: Columns

### Puzzlebomb – October 2016

Puzzlebomb is a monthly puzzle compendium. Issue 58 of Puzzlebomb, for October 2016, can be found here:

Puzzlebomb – Issue 58 – October 2016 (printer-friendly version)

The solutions to Issue 58 will be posted at the same time as Issue 57.

Previous issues of Puzzlebomb, and their solutions, can be found at Puzzlebomb.co.uk.

### The world’s smallest Rubik’s cube is 5.6mm wide and absolutely adorable

I just found this video of a very focused man showing off a teeny tiny Rubik’s cube. It’s 5.6mm on each side, which apparently makes it the smallest in the world, beating some relatively gigantesque efforts of 6mm and larger.

Watch this video; I’ll warn you now that the squee factor gives way to some very dry detail quite quickly.

The cube was made by Tony Fisher, by filing down a 3D-printed 6mm cube. I hadn’t heard of Tony before, which surprises me – his site is full of all sorts of incredible twisty puzzles.

### Carnival of Mathematics 138

The next issue of the Carnival of Mathematics, rounding up blog posts from the month of August, and compiled by Yen Duong, is now online at Baking and Math.

The Carnival rounds up maths blog posts from all over the internet, including some from our own Aperiodical. See our Carnival of Mathematics page for more information.

### Puzzlebomb – September 2016

Puzzlebomb is a monthly puzzle compendium. Issue 57 of Puzzlebomb, for September 2016, can be found here:

Puzzlebomb – Issue 57 – September 2016 (printer-friendly version)

The solutions to Issue 57 can be found here:

Puzzlebomb – Issue 57 – Solutions – September 2016 (printer-friendly version)

Previous issues of Puzzlebomb, and their solutions, can be found at Puzzlebomb.co.uk.

### Photomath can read my writing

I remember when OCR of mathematics was such a difficult problem that there was no good solution. I remember hints some years ago that the then-current version of InftyReader could do a reasonable job of taking a PDF document and converting it into LaTeX code, but it was far from perfect.

Today my phone told me that the app Photomath has an update and now supports handwriting recognition. This means I can write something like this:

and Photomath does this with it:

### Do you use mixed fractions?

I’m at the MATRIX conference in Leeds, where I’ve just been talking to Adam Atkinson. He told me that he’s trying to compile a definitive list of countries that don’t use mixed fractions.

Here’s a mixed fraction: \[ 2 \frac{2}{3} \]

And here’s a non-mixed fraction: \[ \frac{8}{3} \]

Actually, here’s an interesting fact about that number: \[ 2 \sqrt{ \frac{2}{3} } = \sqrt{ 2 \frac{2}{3} } \]

This only makes sense if you believe in mixed fractions (and unicode character U+2062, “invisible times”)

This is going to be one of those wipe-your-bum-standing-up situations: it’s entirely possible that you can be on either side of this divide and not know the other exists. Apparently, in some countries mixed fractions just don’t exist: an integer written next to a fraction is incorrect.

So, to help Adam on his way, I thought I’d start another in our long-running series of Aperiodical Surveys. Please tell us where you live, and if mixed fractions are OK in your book.