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  • Did you solve it? The art of the puzzle
    by Alex Bellos on February 22, 2021 at 5:00 pm

    The solutions to today’s artful problemsEarlier today I set you the following puzzles. The first is a starter problem and the other three were suggested by puzzle guru Rob Eastaway.The nine dotsa) Barely get their fingers underneathb) Crawl underc) Get under if they crouchd) Comfortably walk under Continue reading…

  • Can you solve it? The art of the puzzle
    by Alex Bellos on February 22, 2021 at 7:38 am

    Thinking in and out of the boxUPDATE: The solutions are now up hereWhat makes for a great puzzle? Here’s a golden oldie that certainly qualifies.The nine dotsAn ‘aha’ momentA surprising, counter-intuitive outcomeVisually appealingWhimsically writtenRequires little background expertiseConcisely statedPleasurably teasing: looks very simple but isn’tEasy entry pointa) Barely get their fingers underneath.b) Crawl under.c) Get under if they crouch.d) Comfortably walk under. Continue reading…

  • Did you solve it? Think of a number
    by Alex Bellos on February 8, 2021 at 5:00 pm

    The solution to today’s Q&A puzzleEarlier today I asked you the following puzzle.Ask Johnny Continue reading…

  • Can you solve it? Think of a number
    by Alex Bellos on February 8, 2021 at 7:12 am

    A new twist on the all time classic maths trick UPDATE: the solution can now be read here.“Think of a number” tricks are such a puzzle staple that the BBC even named a kids show after them. (To readers under the age of 40, Think of a Number was hosted by Zoe Ball’s dad Johnny, and to many Britons, this one included, it was an indelible cultural highlight of growing up in the late 1970s/early 1980s.)The following puzzle is a brilliant version of a ‘think of a number’ type problem, which I had not seen until recently. The solution is wonderfully ingenious. If you don’t crack it now, or at all (as it consumes your day, sorry), you will be rewarded when I reveal the answer at 5pm.1 and 500? Yes.1 and 250? No.251 and 375? Yes.251 and 313? No.314 and 345? No.346 and 361? Yes.346 and 354? No355 and 358? Yes355 and 356? NoIs it 358? Yes! (a No here gets you the answer too.) Continue reading…

  • Graham Hoare obituary
    by Tom Doust on January 26, 2021 at 6:22 pm

    My father-in-law, Graham Hoare, who has died aged 85, was a mathematician and teacher who was one of the driving forces behind the Royal Institution’s mathematics masterclasses, which have been providing lively extracurricular maths lessons to gifted young people for almost 40 years. He taught many of the masterclasses and was involved in their administration, having helped Sir Christopher Zeeman to make the idea a reality in the first place.Graham was also letters editor for the Mathematics Today journal, and the Graham Hoare prize is awarded annually to brilliant early career mathematicians. A member of the Mathematical Association, he served on its council and was for many years an assistant editor of its Mathematical Gazette, entertaining and challenging readers with his very own Problem Corner column. Continue reading…

  • Did you solve it? Irresistibly small and intolerably cute
    by Alex Bellos on January 25, 2021 at 5:05 pm

    The answers to today’s micro puzzlesEarlier today I set you 12 micro puzzles. (There’s an extra one at the bottom of this article.)The first six were ‘equatum’ puzzles:LOLLIPOPSEASHELLDELETEDESCAPEESREFERRALCLEVER… 9 + 1 = 10LOLLIPOP…1 + 11 = 6 + 6SEASHELL… 91 + 9 = 100DELETED… 89 + 9 = 98ESCAPEES… 25 x 9 = 225REFERRAL… 43 = 344 ÷ 81. UNOPENED2. MEGABYTE3. PAGANINI4. OUTREACH5. OPERATED6. ISOTOPES Continue reading…

  • Did you solve it? A head for hats
    by Alex Bellos on January 11, 2021 at 5:00 pm

    The solution to today’s problemEarlier today I set you the following puzzle, about three extremely logical people in a line. Each person can only see who is in front of them.A hat seller shows them three white and two black hats. She places a hat on each person and hides the remaining two.WWWWWBWBWWBBBWWBWBBBW Continue reading…

  • Can you solve it? A head for hats
    by Alex Bellos on January 11, 2021 at 7:13 am

    A Q about a queueUPDATE: solution is now upToday’s puzzle concerns these three folk standing in a line, as illustrated below. They are all extremely logical people, and they can only see who is in front of them.A hat seller shows them three white and two black hats. She places a hat on each person and hides the remaining two. Continue reading…

  • Did you solve it? The count reaches ‘twenty, twenty-one’
    by Alex Bellos on December 28, 2020 at 5:02 pm

    The answers to today’s puzzlesEarlier today I set you three puzzles concerning the number 2021, which is the concatenation of two consecutive integers, 20 and 21. Before we get to the problems (and the answers), thanks to reader ConradKnightSocks for alerting me to the brilliant fact that 2021 is also the product of two consecutive prime numbers: 43 x 47.The last time this was the case was 1763, which is 41 x 43. Continue reading…

  • Can you solve it? The count reaches ‘twenty, twenty-one’
    by Alex Bellos on December 28, 2020 at 7:57 am

    Next year in numbersUPDATE: For the solutions and further discussion click here.Count von Count will be fizzing with excitement. For the first time since 1920, the coming year, 2021, consists of two ascending, consecutive numbers. Enjoy this ‘counting date’ while it lasts, people! It ain’t going to happen again for another hundred and one years.Today’s puzzles reveal more arithmetical patterns concerning 2021. Continue reading…

  • The most exciting scientific breakthroughs of 2020, chosen by scientists
    by Guardian Staff on December 20, 2020 at 12:00 pm

    The response to Covid-19 has been momentous but discoveries in AI, diet, conservation, space and beyond, show the power of science to improve the world post-pandemicIn 2020 the race to space changed gear. The May launch of the SpaceX vehicle Crew Dragon was the first time a private vehicle had delivered astronauts to the International Space Station (ISS). It was deeply impressive, but also featureless… sleek, white inner walls replaced the complex instrument panels of old, and it was clear that the two test pilots on board were mostly passengers, with no direct control over the flight. In November, Crew Dragon became the first private spacecraft fully certified by Nasa to transport humans to the ISS and later that month delivered four astronauts to the orbiting station. This taxi may not be cheap, but it’s here to stay and it’s a game-changer. Continue reading…

  • Did you solve it? The colourful truth about elves
    by Alex Bellos on December 14, 2020 at 5:00 pm

    The solution to today’s puzzleEarlier today I set you the following puzzle:Four elves Glarald, Mnementh, Virthana and Tinsel are each wearing tunics of a different colour. At least one of these elves is a liar. (A liar is someone who only says statements that are untrue). During break at elf school, the following conversation is overheard:Glarald: Mnementh wears green. (1)Virthana: The elf in green is a liar. (2)Tinsel: I wear blue. (3)Glarald: I wear yellow. (4)Mnementh: I’m in pink. (5)Virthana: The elf in the red tunic beat Tinsel at the 2020 elf curling championship. I do not play curling. (6)Tinsel: One of us is in yellow. (7)Mnementh: Only one liar is among us. (8)Virthana: I do not wear green. (9)Tinsel: I was beaten by the elf in red at the 2020 elf curling championship. (10) Continue reading…

  • Robin Ince’s 24-hour carnival of comics, comets and the Cure
    by Brian Logan on December 14, 2020 at 2:53 pm

    From Harry Hill to Helen Sharman, Ince’s Christmas mashup of comedy, science and music – Nine Lessons and Carols for Socially Distanced People – reached dizzy heightsIt’s Sunday morning, and Robin Ince is feeling dizzy after twentysomething hours of his 24-hour Christmas comedy-science extravaganza. Maybe it’s the tiredness, he wonders aloud – or maybe it’s that he often feels dizzy when speaking to cosmologists. In that befuddled moment, Ince stumbles upon the justification for Nine Lessons and Carols for Socially Distanced People, this otherwise barmy adventure in round-the-clock science entertainment. Unlike Mark Watson’s marathon comedy shows, say, dizziness is an apt condition in which to engage with Nine Lessons, a day-long DIY The One Show for science geeks, with oddball comedy thrown in whenever the head threatens to stop spinning.It sometimes feels as if it’s held together by no agent more binding than Ince’s personal taste. What else unites the experience of astronauts Helen Sharman and Samantha Cristoforetti with, say, comic John-Luke Roberts’ (brilliant) Chaucer impersonation? Or the geological research of Professor Christopher Jackson with the new songs performed by a barefoot and housebound Robert Smith of the Cure? Precious little, as far as I can see – but maybe I was just too dizzy to make the connections. Continue reading…

  • Can you solve it? The colourful truth about elves
    by Alex Bellos on December 14, 2020 at 7:13 am

    Logic with Santa’s little helpersUPDATE: Solution now up hereHere’s a logic puzzle that was sent in to me by a (very smart) 12-year-old.Four elves Glarald, Mnementh, Virthana and Tinsel are each wearing tunics of a different colour. At least one of these elves is a liar. (A liar is someone who says only statements that are untrue). During a break at elf school, the following conversation is overheard:Glarald: Mnementh wears green.Virthana: The elf in green is a liar.Tinsel: I wear blue.Glarald: I wear yellow.Mnementh: I’m in pink.Virthana: The elf in the red tunic beat Tinsel at the 2020 elf curling championship. I do not play curling.Tinsel: One of us is in yellow.Mnementh: Only one liar is among us.Virthana: I do not wear green.Tinsel: I was beaten by the elf in red at the 2020 elf curling championship. Continue reading…

  • Mathematician explains cracking California Zodiac Killer cipher – video
    on December 12, 2020 at 11:00 am

    The Australian mathematician Samuel Blake describes how he and and two other cryptologists finally solved an encrypted message written by the unnamed serial killer 51 years ago.The FBI confirmed the code, cracked with help from a supercomputer called Spartan, is accurate, but they said it did not help with identificationZodiac: cipher from California serial killer solved after 51 yearsContinue reading…

  • Britain has some of the greatest theoretical scientists, so why won’t it properly fund them? | Thomas Fink
    by Thomas Fink on December 8, 2020 at 10:30 am

    From black holes to consciousness, Nobel-winner Roger Penrose shows the beauty of theory. But it needs more support• Dr Thomas Fink is the director of the London Institute for Mathematical SciencesFrom electromagnetism to quantum mechanics, the greatest scientific discoveries often require little more than a blackboard, a stick of chalk and a congenial place in which to think. The breakthroughs of Roger Penrose, who was recently awarded a Nobel prize for his work on black holes, are a case in point. The British theoretical physicist has made discoveries in areas ranging from the fabric of spacetime to human consciousness. His “Penrose tiles” – two shapes that cover a surface in a never-repeating pattern – aren’t just lovely to look at; they have deep links to the structure of quasicrystals and the theory of computation.Penrose joins a long line of British theoretical scientists stretching back four centuries, from Peter Higgs, GH Hardy and Paul Dirac, to John Dalton and Isaac Newton. But despite the country’s strength at producing theorists, the field of theoretical science receives little support from the UK government. Continue reading…

  • Revealed: Isaac Newton’s attempts to unlock secret code of pyramids
    by Harriet Sherwood on December 6, 2020 at 6:30 am

    Unpublished notes show he believed ancient structures held key to the apocalypseHe is the mathematician who laid the foundations of classical physics, formulated the laws of motion and the law of gravity, and remains the epitome of the age of reason.But Isaac Newton’s secret obsessions with alchemy and obscure branches of theology, which only came to light 200 years after his death, reveal another side to the man who helped shape the modern world. Continue reading…

  • German museum to restore Enigma machine found on seabed
    by AFP in Berlin on December 4, 2020 at 5:10 pm

    Desalination of code machine – which divers thought was ‘old typewriter’ – to take 12 monthsGerman divers who fished an Enigma encryption machine out of the Baltic Sea have handed their rare find over to a museum for restoration.The code machine – which was used by the Nazis to send coded messages during the second world war – was discovered last month by divers on assignment for the environmental group WWF. The group was searching for abandoned fishing nets in the Bay of Gelting off the north-east coast of Germany. Related: How did the Enigma machine work? Continue reading…

  • Did you solve it? The queens of chess
    by Alex Bellos on November 30, 2020 at 5:00 pm

    The solutions to today’s puzzlesEarlier today I set you the following chess-themed conundrums:1. The quintet of queens. Continue reading…

  • Can you solve it? The queens of chess
    by Alex Bellos on November 30, 2020 at 7:11 am

    Puzzles to have you in piecesUPDATE: The solutions are now up hereThanks to the Netflix series The Queen’s Gambit, chess is having a moment. Today’s three puzzles are in homage to world-class female players, both fictitious and real.1. A quintet of queens. Continue reading…