Kit Yates has asked mathematicians to post a picture of themselves using the hashtag #realfaceofmath, in the hope of dispelling the incorrect stereotype that all mathematicians are geeky white guys with beards and glasses (hi!).
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Puzzlebomb – August 2015
Puzzlebomb is a monthly puzzle compendium. Issue 44 of Puzzlebomb, for August 2015, can be found here:
Puzzlebomb – Issue 44 – August 2015
The solutions to Issue 44 can be found here:
Puzzlebomb – Issue 44 – August 2015 – Solutions
Previous issues of Puzzlebomb, and their solutions, can be found here.
Take the 30 second arithmetic challenge
My wife’s grandmother is a fearsome character. She’s in her nineties but still has all her wits about her. In fact, she’s got more than her fair share of wits. Whenever we visit her, she hits me with a barrage of questions and puzzles collected from the last several decades of TV quiz shows and newspaper games pages. My worth as a grandson-in-law is directly proportional to how many answers I get right.
One of her favourite modes of attack is the “30 Second Challenge” from the Daily Mail. It looks like this:
You start with the number on the left, then follow the instructions reading right until you get to the answer at the end. It’s one of Grandma’s favourites because it’s very hard to do in your head when she’s just reading it out!
I decided it would be a fun Sunday morning mental excursion to make a random 30 second challenge generator.
Carnival of Mathematics 124
The next issue of the Carnival of Mathematics, rounding up blog posts from the month of June, and compiled by Manjil, is now online at Gonit Sora.
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.
MacTutor History of Mathematics website creators honoured by LMS
Edmund Robertson & John O’Connor of the University of St. Andrews have been honoured by the London Mathematical Society for their pioneering MacTutor History of Mathematics website hosted at St. Andrews.
On 3rd July it was announced that both men have received the Hirst Prize, and Edmund Robertson has been been invited to give the associated Hirst Lectureship, all part of LMS 150th Anniversary celebrations.
Puzzlebomb – July 2015
Puzzlebomb is a monthly puzzle compendium. Issue 43 of Puzzlebomb, for July 2015, can be found here:
Puzzlebomb – Issue 43 – July 2015
The solutions to Issue 43 can be found here:
Puzzlebomb – Issue 43 – July 2015 – Solutions
Previous issues of Puzzlebomb, and their solutions, can be found here.
How many ways to shuffle a pack of cards?
This is an excerpt from friend of The Aperiodical, Matt Parker’s book, “Things to Make and Do in the Fourth Dimension”, which is out now in paperback.
There’s a lovely function in mathematics called the factorial function, which involves multiplying the input number by every number smaller than it. For example: $\operatorname{factorial}(5) = 5 \times 4 \times 3 \times 2 \times 1 = 120$. The values of factorials get alarmingly big so, conveniently, the function is written in shorthand as an exclamation mark. So when a mathematician writes things like $5! = 120$ and $13! = 6,\!227,\!020,\!800$ the exclamation mark represents both factorial and pure excitement. Factorials are mathematically interesting for several reasons, possibly the most common being that they represent the ways objects can be shuffled. If you have thirteen cards to shuffle, then there are thirteen possible cards you could put down first. You then have the remaining twelve cards as options for the second one, eleven for the next, and so on – giving just over 6 billion possibilities for arranging a mere thirteen cards.