### Did you solve it? 2019 in numbers

Earlier today I set you the following puzzles about the number 2019 1) Date jam (i) Using only the digits 2, 0, 1 and 9, create expressions that equal all of the numbers from 0 to 12. The expressions can include any of the arithmetical symbols +, –, x, ÷ and √, and brackets. Here’s…

### Can you solve it? 2019 in numbers

To welcome the New Year, we’re going to celebrate the number 2019. Here’s one numerical factoid readers may find charming: Ed Southall (@solvemymaths) 2019 is the smallest number that can be written in 6 ways as the sum of the squares of 3 primes: 7² + 11² + 43² = 2019 7² + 17² +…

### Mobius kaleidocycles: Sensational structures with potential applications

Dr. Johannes Schönke and Prof. Eliot Fried created a variety of Möbius Kaleidocycles with different numbers of hinges from folded paper and 3D printed materials. Credit: OIST Kaleidocycles are found where science, math, and art meet. The objects resemble geometric sculptures that might be found in a modern art museum, but it is the motions…

### Did you solve it? Can you speak Twitter?

Earlier today I set you a quiz about Twitter slang, and a maths puzzle. Here are the answers, with discussion and workings! The following ten words and phrases emerged in Twitter communities, and are beginning to cross over to general users. Under each word or phrase are two possible definitions. Which is the correct one?…

### Can you solve it? Do you speak Twitter?

This week, two puzzles about social media. The first is something new for this column, a language quiz, and below it is the usual fare, a mathematical conundrum. In the 1990s, I used to write a weekly column in the Guardian about language. Were I to write the column today, one of my first subjects…

### Lindsay Logan obituary

My father, Lindsay Logan, who has died aged 79, was emeritus professor of Dundee University and a distinguished educationist. He was head of the maths department at Northern College, Dundee, before it amalgamated with the university, where he became head of maths education. Through his passion for the teaching of mathematics, he made a significant…

### Can social interactions affect spread of disease?

Most real-world systems, such as biological, social, and economic schemes evolve constantly. The dynamics of such systems are characterized by significantly enhanced activity levels over short periods of time (or “bursts”) followed by long periods of inactivity. This is true of social communities, in which the pattern of connections between individuals progresses over time, and…

### Mathematical model offers new strategies for urban burglary prevention

As with most crime, the highest rates of burglary occur in urban communities since large metropolitan areas generally boast more concentrated wealth. Big cities also allow burglars to maintain anonymity and evade authority while offering ample opportunities for discreet disposal of stolen property. Burglars observe their target cities with the careful attention of urban planners,…

### Did you solve it? An Aboriginal family puzzle

Earlier today I set you the following puzzle: Aboriginal groups are divided into subgroups, called “skins.” Your skin is determined at birth, based on your parents’ skins, and it does not change in your lifetime. Your skin will determine certain social rules, such as who you are allowed to marry. The Warlpiri, who live northwest…

### Can you solve it? An Aboriginal family puzzle

Hi guzzlers, Today I have a logic puzzle based on the complex kinship rules found in Australian Aboriginal society. Aboriginal groups are divided into subgroups, called “skins.” Your skin is determined at birth, based on your parents’ skins, and it does not change in your lifetime. Your skin will determine certain social rules, such as…