Crossnumber winners, issue 10

by Matthew Scroggs. Published on 26 March 2020.

Hello everyone! It’s time to announce the winners of the Chalkdust prize crossnumber #10! Before we reveal the winners, here is the solution of the crossnumber.

1	0	8	9	0		2	2	2	2	2	2	2	2	2
1			9		5			2	8			6	7	5
1	0	8	9		5		2	5	8			6
1			9	7	5	4	3	2	0			4	1	2
0			0		5			4	1	1	9		1	0
0		1	0	7		9	6	7	8	9	6	3	0	1
	4	2							1	9	8		1	0
8	9	1	8	7	1	6	5	1	4	3	1	2	1	1
1	4		7	2	0							1	0
7	4	5	6	3	4	1	2	3		5	9	4		9
8	4		5	5	5	9			4		9			9
8	9	1			2	6	1	8	1	6	9			9
		2			4	9	5		1		1	0	8	9
8	5	2			4	9			9		8			0
2	2	2	2	2	2	2	2	2		1	0	8	9	0

The sum of the across clues was 891873821817653.

There were 40 entries, 37 of which were correct. The randomly selected winners are:

Laurence, who wins a £100 Maths Gear goody bag,
Robert Hannan, who wins a Chalkdust T-shirt,
James, who wins a Chalkdust T-shirt,
Thomas Smith, who wins a Chalkdust T-shirt.

Well done to Laurence, Robert, James and Thomas, and thanks to everyone else who attempted the crossnumber. See you shortly in issue 11…

Prize crossnumber, Issue 10

by Chalkdust. Published on 23 October 2019.

Our original prize crossnumber is featured on pages 48 and 49 of Issue 10.

Download Crossnumber #10 as a PDF, or read on!
Submit your answer

Rules

Although many of the clues have multiple answers, there is only one solution to the completed crossnumber. As usual, no numbers begin with 0. Use of Python, OEIS, Wikipedia, etc. is advised for some of the clues.
One randomly selected correct answer will win a £100 Maths Gear goody bag, including non-transitive dice, a Festival of the Spoken Nerd DVD, and much, much more. Three randomly selected runners up will win a Chalkdust T-shirt. Maths Gear is a website that sells nerdy things worldwide, with free UK shipping.
To enter, enter the sum of the across clues below by 2 February 2020. Only one entry per person will be accepted. Winners will be notified by email and announced on our blog by 14 March 2020.

Correction: Clue 13A has been corrected to “49A reversed” instead of “49D reversed”.
Correction: Clue 38D has been corrected to “33A less than 39D” instead of “33A less than 39A”.
Clarificiation: The triangle in 6D is a right-angled triangle.
Continue reading →

Dear Dirichlet, Issue 10

by Chalkdust. Published on 23 October 2019.

Moonlighting agony uncle Professor Dirichlet answers your personal problems. Want the prof’s help? Send your problems to deardirichlet@chalkdustmagazine.com.

Dear Dirichlet,

Boy, am I in a world of woes! In the coming months, I have to go into surgery six times for a whole host of illnesses. To its credit, the hospital has allowed me to arrange my own schedule. In your doctoral opinion, which procedures should I undergo first?

— Under the weather, Cambridge

Continue reading →

Comic: The Inverse Homotopy, part 7

by Tom Hockenhull. Published on 23 October 2019.

Which mathematician are you?

by Chalkdust. Published on 23 October 2019.

On the cover: Islamic geometry

by Emily Maw. Published on 23 October 2019.

From the exquisite patterns of the Alhambra palace in Spain to a jigsaw puzzle on a rainy day, tessellations (tilings of the plane using shapes with no overlaps or gaps) are everywhere. They are sometimes used for practical reasons: providing durable and water-resistant surfaces, or for efficiencies of space (like hexagons in a honeycomb). And sometimes they are there for aesthetic reasons: tessellations are known to have been used in architecture since at least 4000BC when the Sumerians decorated walls with patterns of clay tiles. Continue reading →

What’s hot and what’s not, Issue 10

by Chalkdust. Published on 23 October 2019.

Maths is a fickle world. Stay à la mode with our guide to the latest trends.

HOT Issue 10

We’re so excited about releasing issue 10!

NOT Issue 3628800

Wait another 1.8 million years for this one? No thanks.

Continue reading →

Top Ten: issues of Chalkdust

by Chalkdust. Published on 23 October 2019.

This issue, Top Ten features the top ten issues of Chalkdust! Then vote here on the top ten pictures of scorpions for issue 11!

At 10, it’s the tenth most egg-cellent issue of Chalkdust: issue 06.

At 9, it’s issue 02, the difficult second issue.

At 8, it’s John Lennon’s latest avant garde composition: issue 09. issue 09. issue 09. issue 09. issue 09. issue 09. issue 09. issue 09. issue 09. issue 09. issue 09. issue 09.

At 7, it’s Puff, the Magic Dragon Curves by Peter, issue 05 and Mary.

At 6, it’s the issue that will explain why the vote to put this issue in sixth place is unfair: issue 03.

At 5, it’s When I’m issue 04 by The Beatles.

At 4, it’s the only issue printed on A5 paper (which was a mistake, just like the minidisc): issue 01.

At 3, it’s You’re my number three issue of Chalkdust by S Club issue 07.

After a whole year at number 1, it’s the issue that’s finally been knocked down to number 2: issue 08.

Topping the pops this issue, it’s a new entry and a brand new release: issue 10.

Page 3 model: Bees

by Eleanor Doman. Published on 23 October 2019.

If you model rabbits under ideal circumstances, you may find that the number of pairs of rabbits each month follows the Fibonacci sequence.

In this case, ‘ideal circumstances’ is a euphemism for nonsense, as your assumptions would include blatant untruths such as “rabbits mate once a month every month except their first month alive”, “a pair of rabbits gives birth to exactly one pair of rabbits per month”, and “the hutch is infinitely big (and hence Starsky is very squashed)”.

Fibonacci numbers, however, are not completely absent from nature. They accurately describe a vastly superior animal: the honeybee.

Male bees (drones) come from unfertilised eggs, and so they only have one parent — the queen.
Female bees (workers or queens) come from fertilised eggs and so have two parents — the current queen and a drone.

If you follow a drone’s family tree backwards, you will see that a drone has: