
Sport in Hyperbolic Space
Imagining a world of playing baseball and golf with hyperbolic geometry, rather than Euclidean.
Featuring Dick Canary


James H Simons
He became one of the world's richest men using mathematics  now he gives money back to math and science.
Featuring Jim Simons 

Monkeys and Coconuts
A puzzle that stumpedmany people  prepare for 'negative coconuts'. Animation by Pete McPartlan.
Featuring Tony Padilla 





Telescope Time
An astronomy/math collaboration in search of a fairer system for allocating telescopes.
Featuring Mike Merrifield 

Relationship Equation
Can mathematics be used to describe and predict the future of relationships?
Featuring Hannah Fry 

Ditching the Fifth Axiom
Doing away with Euclid's fifth axiom led to the birth of Hyperbolic Geometry.
Featuring Caleb Ashley 



How to Shuffle
What oi f the best way to shuffle cards. Riffle shuffles vs Overhand.
Featuring Persi Diaconis 





Bridge to Fermat
There was more to cracking Fermat's Last Theorem than Andrew Wiles' extraordnary proof.
Featuring Ken Ribet 

58 and Lingusitics
How various other languges handle numbers, from Danish to Klingon.
Featuring Tom Scott


Useless Imaginary Numbers
The first people to stumble over imaginary numbers (namely the square root of 15) thought it was "subtle" and "useless".
Featuring Barry Mazur 

Little Professor Toy
The Texas Instruments Little Professor  a love letter from Dr Grime.
Featuring James Grime 



Super Egg
Super ellipses and and super eggs  and traffic managemnet in Stockholm.
Featuring Alex Bellos 

Should you catch a coin
Is it more random to toss a coin or spin in on table? And if you flip it, should you catch it?
Featuring Persi Diaconis 



Rock Paper Scissors
A little mathematics behind this famous and seemingly simply game. What is the best strategy?
Featuring Hannah Fry 

Rock Paper Lizards
Some extra stuff on rock paper scissors  including how it applies to the animal kingdom.
Featuring Hannah Fry 



Heptadecagon
The 17gon is part of an amazing story about Gauss. And led to the address 17 Gauss Way for MSRI!
Featuring David Eisenbud 

Dots and Boxes
Game theory legend Elwyn Berlekamp on how to always win at Dots and Boxes.
Featuring Elwyn Berlekamp 

Perfect Proof
A proof connecting Mersenne Primes and Perfect Numbers.
Featuring Matt Parker 



Dragon Curve Error
Living with a wrong turn. Piet Hein. Err and err and err again.
Featuring Donald Knuth 



Sound Checks
A compilation of Numberphile sound checks, asking people what they had for breakfast? 

Euclidean Geometry
Much can be accomplished using just a straight edge and compass  but not everything!
Featuring Zsuzsanna Dancso 

Infinite Fractions
SternBrocot numbers, fractions and rational numbers.
Featuring Matt Parker 

Imaginary Erdos Numbers
Many people are familiar with Erdos Numbers  but how do you end up with an imaginary one?
Featuring Ron Graham 

Animation at Pixar
How do Pixar characters look so smooth on screen? With mathematics of course!
Featuring Tony DeRose 

Leyland Numbers
Some recreational mathmematics and nostalgia for an old Aussie TV show.
Featuring Ed Copeland 

Equilatral Triangles
A bogus proof that ALL triangle are equilateral  but it looks like nothing was wrong!?
Featuring Carlo Sequin 

Mile of Pi
Printing Pi to one million decimal places and then rolling it out on a runway.
Featuring Matt Parker and Brady Haran 



Lunes
Lunes and Hippocates of Chios. Squaring the Circle. Geometry. Polygons. Spearheads. Crescents.
Featuring Barry Mazur 

Brady Numbers
The newly 'invented' Brady Numbers show the Fibonacci Numbers' link with the golden ratio may not be so special.
Featuring Matt Parker 





Wobbly Circles
How to join two circles in a very special way.
Featuring Matt Parker 

Friedman Numbers
Some classic recreational mathematics using basic math operations.
Featuring Ed Copeland 

Lucas Numbers
A series of numbers with a better claim to a "golden Ratio" link.
Featuring Matt Parker 

Golden Proof
A proof that Fibonacci Numbers do not have such a great claim to the golden ratio.
Featuring Matt Parker 



Magic Hexagon
The only known Magic Hexagon and how to prove it. Plus some Magic Squares.
Featuring James Grime 

Wobbly Tables
How to fix a wobblytable with math. Includes the intermediate value theorem.
Featuring Matthias Kreck 

Boring Numbers
Smallest Uninteresting Number. Paradox. 14972. Boring Number. OEIS. Sequences. Contradiction.
Featuring Tony Padilla 

Look and Say Sequence
LookandSay Sequence. Conway Constant. Audioactive Numbers. Roman Numerals. Elements. Periodic Table.
Featuring John Conway 

Wilson Primes
5 13 and 563 are the only known Wilson Primes. Primality Test. Factorials.
Featuring James Grime 



What is Graham's Number
What is Graham's Number. Dimensions. Cubes. Hypercubes. Vertices. Ramsey Theory.
Featuring Ron Graham 





Happy Ending Problem
Paul Ardos. George Szekeres. Esther Klein. Convex polygon. Concave. Points. Ramsey Theory. Ronald Graham.
Featuring Ron Graham 

Cake Cutting
A new (old) way to keep your cake fresh. Francis Galton. Nature. Featuring Alex Bellos 



Odd Polynomials
Why polynomials with an odd degree will have at least one real root/solution/zero. Functions. Dedekind Cuts. Featuring David Eisenbud 

Monty Hall Problem
The Monty Hall Problem. Let's Make a Deal. Probability. Stick or Switch. Featuring Lisa Goldberg 

Monty Hall Problem
More on the Monty Hall Problem. Another explanation from Numberphile's creator Featuring Brady Haran 

Friends and Strangers
A Facebook twist on the wellknown Friends and Strangers Theorem. Ramsey Theory. Featuring Simon Pampena 

Monster Group
Monster Group. Sporadic Groups. Group Theory. Featuring John Conway and Tim Burness 



Math Fable
Scale, similarity and the Pythagorean Theorem. Featuring Barry Mazur 

2048
A handful of professors react to the popular game 2048. 





Poincaré Conjecture
The famed Poincaré Conjecture, the Millennium Problem famously solved by Grigori Pereleman. Featuring Katie Steckles and James Isenberg 

Ricci Flow
This technique was used to crack the Poincaré Conjecture. Featuring James Isenberg 

Soccer Ball
Using the Euler Charcteristic on a soccer ball (football). Featuring Teena Gerhardt 

Epic Circles
Circles. Circle Inversion. Pappus Chains. Featuring Simon Pampena 



Mobius Bridges
Mobius Shapes. Houses. Bridges. Architecture. Featuring Carlo Sequin 

Dominoes Extras
More on using dominoes to replicate computer circuits. Featuring Matt Parker 



Infographic
Infographic. Napoleon. Russia. Charles Joseph Minard. Featuring James Grime 



Pi and Rivers
Sinuosity. Pi. Averages. River Lengths. Oxbow lakes. Featuring James Grime 

Prog Rock Pi
Progressive Rock song heavily based on Pi and Tau. Featuring Alan Stewart 

Brussels Sprouts
Planar Graphs. Brussels Sprouts Game. Euler's Identity. Featuring Teena Gerhardt 

Riemann Hypothesis
Riemann Zeta Function. Riemann Hypothesis. Millennium Prizes. Featuring Edward Frenkel 







Prime Test
Prime Numbers. AKS Test. Featuring James Grime 

Fifth Root
Fifth Root. Trick. Eulers Theorem. Featuring Carlo Séquin 



Twisted Toroids
Torus. Toroids. Topology. Mobius Strips. Mobius Bands. Featuring Carlo Séquin 

Knight's Tour
Chess. Knight's Tour. Hamiltonian Graph. Magic Squares. Magic Knight's Tours. Featuring Brady Haran 

1+2+3+4 (extra footage)
Analytical Continuation. Zeta Function. Ramanujan Summation. Minue one twelfth. Astounding Result. Featuring Tony Padilla and Ed Copeland 

1+2+3+4
Analytic Continuation. Zeta Function. Ramanujan Summation. Minus one twelfth. Astounding Result. Featuring Tony Padilla and Ed Copeland 

Pi Visualisation
Artistic views of Pi and other numbers. Art by Martin Krzywinski and Cristian Ilies Vasile. Featuring James Grime 

Calculator Watch Unboxing
Calculator Watch Unboxing. Featuring Matt Parker 

Casio fx85GT Unboxing
Calculator Unboxing Series. Featuring Matt Parker 

NSA Surveillance Extra Footage
National Security Agency. Encryption. Security. Featuring Edward Frenkel 

NSA Surveillance
National Security Agency. Encryption. Security. Featuring Edward Frenkel 

Pebbling a Chessboard  Pt I
An elegant proof involving cloning pebbles on an infinite chessboard. Featuring Zvezdelina Stankova 

10:10 in Watch Ads
Just some fun  it is always 10:10 in watch advertisements 

Connect Four
Connect Four. Games. Mathematically Solved.
Featuring Brady Haran. 

Futurama and Taxicab Numbers
1729. 87,539,319. Ramanujan. Hardy. The TV show Futurama.
Featuring Simon Singh. 

Shapes and Solids of Constant Width
Tetrahedron. Reuleaux triangle. UK 50p coin.
Featuring Steve Mould. 

Pi and Four Fingers
Pi in the Simpsons. Digits of Pi. Apu. Four finers. Five fingers. Base 8. Base 10.
Featuring Simon Singh. 

Cyclic Numbers
142857. Seventh. Prime Numbers. Cycles. Digits.
Featuring Tony Padilla. 

Sloane's Gap
OEIS. Integer Database. Frequency of Numbers.
Featuring James Grime. 

Simpsons and Fermat
Pierre de Fermat. Fermat's Last Theorem. Proof. Andrew Wiles.
Featuring Simon Singh. 

Math and Politics
Politics. Mathematics. Do political beliefes affect math ability? Gun control.
Featuring James Grime. 

Calculator Unboxing
Calculator unboxings. Review. Morrisons Desktop Calculator, WHSmith Scientific Calculator and Canon AS120.
Featuring Matt Parker. 

Fermat's Last Theorem
Pierre de Fermat. Fermat's Last Theorem. Proof. Andrew Wiles.
Featuring Simon Singh. 

Pisano Period
Fibonacci Sequence. Moudulo. Pattern. Repeats. Leonardo Pisano.
Featuring James Grime. 

The Primer
Prime Numbers. Gaps. Karl Lautman. Sequence. Red Button.
Featuring James Grime. 

Log Tables
Logarithms. Log10. Decadic Logarithm. Multiplication. Division.
Featuring Roger Bowley. 

Phone Button LayOut
Telephone Keypads. Human Factors. Bell Labs. Rotary Phones.
Featuring Sarah Wiseman. 

Can Fish Count?
Fish. Numerosity. Number Cognition. Research into whether fish recognise the number of fish in other groups.
Featuring Brian Butterworth. 

Brady Haran Live
Live HangOut wth Numberphile's creator. Video journalist. Discussing his varius projects.
Featuring Brady Haran. 
 The Prime Number Theorem Why Primes are like Weeds. Distribution of Prime Numbers. Natural Log. Density of Primes. Featuring James Grime. 
 Mills' Constant
Mills' Constant and Prime Numbers. William H Mills. Prime Gaps.
Featuring James Grime. 
 Confused Americans
Americans deal with numbers in the UK. England. USA. Linguistics.
Featuring CGP Grey and Lynne Murphy. 
 Numberline
Number Line. How do you measure with numbers if they have no size? Point. Points.
Featuring Simon Pampena. 
 Six Sequences
Number sequences. Khintchine's constant, Wieferich primes, Golomb's sequence, Largest metadrome in base n, All 7's and Wild Numbers. Integers.
Featuring Tony Padilla. 
 More Numberline
More about the number line. Points.
Featuring Simon Pampena. 
 Ulam Spiral
Spirals and Prime Numbers. Stanislaw Ulam. Prime Spiral. Quadratic Polynomials.
Featuring James Grime. 
 Grandi's Series
Grandi's Series and Thomson's Lamp. Guido Grandi. Diveregent Series.
Featuring James Grime. 
 Infinity Paradoxes
Infinity paradoxes. Hilbert's Hotel. Gabriel's Trumpet.
Featuring Mark Jago. 
 41 More on prime numbers and Ulam's Spiral  this time focusing on the number 41 and Arthur C. Clarke. Featuring James Clewett. 
 Cicadas
How nature uses prime numbers. Why do cicadas emerge every 17 years? Primes.
Featuring Steve Mould. 
 Math or Maths?
Linguist. Math (USstyle) and Maths (Britishstyle). Mathematics. Plural.
Featuring Lynne Murphy. 
 Random Numbers
Using radioactive material to generate random numbers. 7. Seven. Strontium.
Featuring James Clewett. 
 Illegal Numbers
A look at copyright, security, and the concept of illegal numbers. Steganographic.
Featuring James Grime. 
 Pandigital
Pandigital. Phone number. Integer. Base. 1023456789. 381,654,729.
Featuring James Grime and Brady Haran. 
 Brown Numbers
Brocard's Problem. Paul Erdos.
Featuring Ed Copeland. 
 Alankey86 Mathmatical Music with Alam Stewart, Numberphile's music maestro. Featuring Alan Stewart and Brady Haran. 
 Transcendental
What is a Transcendental number? Numbers like e and Pi cannot be made using normal algebra. Complex. Algebraic.
Featuring Simon Pampena. 
 More Synaesethesia More on number/color synesthesia, including your questions for with Alex Dainis Featuring Alex Dainis and Brady Haran. 
 Googol Song
Trying to sing a Googol and Googolplex. Music. Comedy.
Featuring Helen Arney & Matt Parker. 
 Math Jokes Explained
Some classic math jokes explained in forensic fashion. Comedy. Standupmaths.
Featuring Matt Parker. 
 Infinite Primes How do we know there are an infinite number of primes? Dr James Grime explains, with a bit of help from Euclid. Featuring James Grime. 
 Math Jokes in Bases
Math jokes using different bases, because not all are in base 10. OCT31. DEC25.
Featuring Matt Parker. 
 Enigma The Nazi's Enigma Machine, was a crucial part of World War II. This video explores the mathematics behind it. Featuring James Grime. 
 Zero Factorial
0! = 1. Proof. Arrange objects.
Featuring James Grime. 
 Pie with Pies
Using hundreds of real delicious pies to calculate Pi in the real world. Pukka Pies. Circumference. Radius. Diamater.
Featuring Matt Parker. 
 Prime Gap An exciting paper about gaps between prime numbers  a step closer to proving the twin prime conjecture. Featuring Ed Copeland & Tony Padilla. 
 Fibonacci Tartan
A tartan, whose pattern is based on the Fibonacci Sequence. Ribbon. Cloth.
Featuring Brady Haran. 
 Redefining Pi The State of Indiana (USA) nearly passed a law which would have made Pi equal 3.2  strange but true. Featuring James Grime. 
 Zeno's Paradox A 2,500 year old paradox from Zeno that has interested mathmeticians, phycisists, and philosophers. (Clap) Featuring James Grime. 
 Safe Cracking
A chat about some of the ways legendary physicist Richard Feynman cracked safes (filing cabinets) at Los Alamos.
Featuring Roger Bowley. 
 Real Good Will Hunting Who was the real Good Will Hunting? George Dantzig, William Sidis, Srinivasa Ramanujan?
Featuring James Grime. 
 Squaring Circle Squaring a circle? Impossible? Can a square and a circle have the same area? Featuring James Grime. 
 Good Will Hunting
The Good Will Hunting maths problem. Matt Damon. Homeomorphically irreducible trees.
Featuring James Grime. 
 French Numbers
French counting. France. Phone numbers and commas. 79.
Featuring Paul Smith. 
 Match Day
We join the Opta team harvesting data from football/soccer matches on match day. Statistics.
Featuring Matt Furniss from Opta. 
 Nepal Numbers
A quick video from Brady Haran, after his return from Nepal, with number news. 1. One.
Featuring Brady Haran. 
 19 out of 20
Try getting a 20 (highest grade) in France. Nearly impossible. Language. Culture.
Featuring Paul Smith. 
 Dragon Curve to Music
The Dragon Curve animated and set to music. Alankey86.
Featuring Pierre Bernard and Alan Stewart. 
 Pi and the size of the Universe Pi is famously calculated to trillions of digits  but Dr James Grime says 39 is probably enough. Featuring James Grime. 
 Rubik's Cube
All the Numberphile videos on Rubik's Cube. Inc God's Number. 
 Enigma Flaw The Nazis' Enigma Machine had a fatal flaw, which allowed the Allies to break the code. Featuring James Grime. 
 Numbers and Words How the brain processes numbers vs. how it processes words. Featuring Brian Butterworth. 
 Smith Numbers What is a Smith number? 4937775 is one. Find out why here. Featuring Ed Copeland. 
 Zero Even Is Zero even? Featuring James Grime and Roger Bowley. 
 RSA Encryption Banks, Facebook, Twitter and Google use epic numbers  based on prime factors  to keep our Internet secrets. This is RSA publickey encryption. Featuring James Grime. 
 Benford's Law What is the most popular leading digit? Benford's Law tells what it most likely will be. Featuring Steve Mould. 
 Anatomy of a Goal A numerical look at a World Cup winning goal. Featuring Sam Green and Opta. 
 301 YouTube Views Why does the YouTube video view counter seem to get stuck on 301 views? Featuring Brady Haran and Ted Hamilton. 
 Unix Time Time will "end" for 32bit computers on 19 January, 2038. Are you prepared? Featuring James Clewett. 
 Tau vs Pi Let's Get Ready To Rumble!!!! It's a Tau vs Pi smackdown. Featuring Steve Mould and Matt Parker. 
 Graham's Number It's the ledgendary Graham's Number. A number so epic it will collapse your brain into a black hole! Featuring Tony Padilla and Matt Parker. 
 The Pi Collection All the Numberphile videos on Pi and its awesomeness. 
 Yahtzee All of the Numberphile videos about Yahtzee. 
 Tau Song A composition combining Tau and Phi. Featuring Phil Moriarty. 
 Spaghetti Numbers What's the biggest number you can make in a tin of Numberetti? Featuring Brady Haran and neighbor kids. 
 Live with James Grime Get to know a Numberphile regular contributer  Dr. James Grime! Featuring James Grime and Brady Haran. 
 Platonic Solids What are platonic solids, and why are there only five of them? Featuring James Grime and Katie Steckles. 
 Card Trick
Learn a numbery card trick. Cards. Featuring Matt Parker. 
 Golden Ratio Song
Math Metal Song about the Golden Ratio. Dave Brown. Heavy Maetal. Phi. Featuring Phil Moriarty and Dave Brown. 
 Dividing by Zero
Although zero is important, it can be dangerous. Division. Infinity. Featuring James Grime and Matt Parker. 
 ViHart and Tetrahedrons
Mathemusician ViHart tackled Numberphile's Yahtzee challenge  but in her own style of course. Dice. Probability. Featuring ViHart. 
 Largest Prime A new largest known prime number is also a Mersenne Prime. Featuring Tony Padilla. 
 Tau Should Pi be replaced by Tau? The smackdown begins. Featuring Phil Moriarty. 
 Numbers and Words What is your favourite number? Viewers comment. Featuring Brady Haran. 
 Kids Get Money The neighbor kids gets paid for their Numberetti brown paper. Featuring Brady Haran and neighbor kids. 
 Root 2 The square root of two is a fascinating number with implications in unlikely places. Featuring James Grime and Roger Bowley. 
 42 Why is 42 so popular? Featuring James Grime, Gerardo Adesso and Phil Moriarty. 
 Chicken Nuggets 43 is a special number in the world of Chicken McNuggets. Featuring James Grime. 
 Favourite Numbers Top YouTubers reveal their favourite numbers. Featuring Famous YouTubers. 
 Borremean Rings Fun with Borromean Rings. Featuring John Hunton. 
 Perfect Games Perfect numbers in sports and games. Featuring Brady Haran. 
 Keith Numbers 197 is one of the rare "Keith Numbers". Featuring Ed Copeland. 
 23 Googol and Googolplex Featuring Tony Padilla and Ria Symonds. 
 Turn to 400 James Clewett graphs one of his favourite books and explains the significance of 400. Featuring James Clewett. 
 Making Golden Ratio Song Details "behind the scenes" from the making of our Golden Ratio anthem. Featuring Phil Moriarty and Dave Brown. 
 Brown's Criterion A "little mathematical trick" which can be performed with powers of two, Fibonacci numbers and prime numbers. Featuring James Grime. 
 Nepal Flag The Nepal constitution has detailed geometrical specifications for its flag. Featuring James Grime. 
 Longest Time What is the longest finite time ever calculated by a physicist? Featuring Tony Padilla. 
 Billions and Trillions
We discuss millions, billions, trillions and centillions. Quadrillions, sextillions, milliards, billiards and the Greek myriad. Featuring James Grime and Tony Padilla. 
 1 not prime Is 1 a prime number? Apparently not. Featuring James Grime. 
 Vampire Numbers We sink our teeth into vampire numbers. Featuring James Grime and Ed Copeland. 
 27 Mathematician Katie Steckles in why she likes 27 and why it makes a special appearance in Pi. Featuring Katie Steckles. 
 Advent Calendar It's a Numberphile Advent Calendar. Featuring Brady Haran. 
 Do numbers exist? Do numbers EXIST? You know, REALLY EXIST? Featuring Dr. Jonathan Tallant. 
 Curta Calculator The Curta is a pocketsized, mechanical, digital calculator, invented by Curt Herzstark. Featuring Alex Bellow. 
 Usain Bolt and 9.63 Would Albert Einstein agree that Usain Bolt ran the 100m in 9.63 seconds? Featuring Tony Padilla. 
 8848 Mt. Everest is really tall. How tall? It MIGHT be 8848 meters, we think. Featuring Brady Haran. 
 Dragon Curve Beautiful Dragon Curves, Fractals and Jurassic Park. Featuring Rob Eastaway. 
 Base 12 We marked the date 12/12/12 with a video about the merits of the dozenal/duodecimal system. Featuring James Grime. 
 666 666 (and sometimes 616) is the notorious Number of the Beast. What's all that about? And what has roulette got to do with it!? Featuring Pete Watts and James Grime. 
 Three is Everywhere Almost all numbers contain the digit three  and we can prove it!? Featuring James Grime. 
 Avogadro's Number Discussing Avogadro's Number on Mole Day. Featuring Martyn Poliakoff. 
 Infinity Sometimes infinity is even bigger than you think. Featuring James Grime. 
 27 Card Trick What's the 'most mathematically beautiful' card trick? Find out here. Featuring Matt Parker. 
 Batman Curve Atomic batteries to power! Turbines to speed! The amazing Batman equation. Featuring James Grime. 
 The Internet if Full What do we do now that all 4,294,967,296 IP addresses have been given out? Featuring James Clewett. 
 220 and 284 220 and 284 get along fairly well? They are one example of socalled amicable numbers. Featuring James Grime. 
 7 Happy Number What makes a number happy? Ask the number 7. Featuring Dr. Ria Symonds. 
 Melancoil "Happification" and the resulting structures it creates. Includes the fascinating Melancoil!. Featuring Matt Parker. 
 255 Binary and PacMan Explaining binary to understand why PacMan becomes unplayable after 255 levels. Featuring James Clewett. 
 Lucky Numbers Why are some numbers "lucky" and some are not? Featuring Dr. Ria Symonds. 
 1729 & Taxi Cabs The number 1729 is "famous" among mathematicians. Why? Featuring James Grime and Roger Bowley. 
 Dyscalculia Dyscalculia is a learning disability involving mathematics and numbers. Featuring Brian Butterworth. 
 One to One Million How fast can you add the digits one to to one million? Pretty fast with this trick. Featuring James Grime. 
 163 163 is a strange and complex number. Featuring Alex Clark. 
 23 What's the probability that two people on the football/soccer pitch share a birthday? Surprisingly low. Featuring James Grime. 
 17 and suduko 17 is the minimum number of clues required to give a unique sudoku solution  but how did mathematicians prove this? Featuring James Grime. 
 Grafting Numbers Square roots, strange patterns and a mysterious constant  what are Matt's "grafting numbers" all about? And why is computer programming like skydiving? Featuring Matt Parker. 
 31 Mersenne Prime 31 is one of the special Mersenne Prime numbers. They are related to perfect numbers. Featuring James Grime. 
 Chinese Numbers 8 and 6 are lucky but 4 is unlucky... if you're Chinese! Featuring Xiaohui Yuan. 
 998001 998,001 and its Mysterious Recurring Decimals. Featuring James Grime. 
 10 Factorial "I'll see you again in 10! seconds!"  When will I see you again? Featuring James Grime. 
 Sexy Prime Sexy primes are prime numbers which differ by six  but what is an "Octomus Prime"??? Featuring James Grime. 
 6174 Try 69! on your calculator, but don't even think about 70! Featuring Professor Laurence Eaves. 
 Leap Year Why do we have lear year? Because our calendar is a mess. Featuring Meghan Gray. 
 8128 For many years, 8128 was the largest known perfect number. But what is a perfect number? Featuring James Grime. 
 Abel Prize Endre Szemerédi wins the mathematics equivalent of the Nobel Prize  the 2012 Abel Prize. He wins 6,000,000 Norwegian Kroner for his troubles. Featuring James Grime and David Hodge. 
 6174 6174 is also known as Kaprekar's Constant. Featuring Roger Bowley. 
 Zequals Ruthless rounding using the "zequals" estimation method. Featuring Rob Eastaway. 
 15 and bumfit Numbers can be interesting when studied in different languages and dialects  such as in Lincolnshire where we have dik, figgit and bumfit. Featuring Roger Bowley. 
 37 37. Who would have thought it was such fun? Featuring Matt Parker. 
 Sixty The ancient Babylonians used a number system with base 60 (sexagesimal). Why? Featuring Thomas Woolley. 
 153 153 thinks it's great. That's why it's a greatexample of a narcissistic number. Featuring Dr. Ria Symonds. 
 5 and tiling Why fivesided figures pose a problem, and a bit about the importance of Penrose Tiling. Featuring John Hunton. 
 137 Pythagorean Primes. Why 5, 13 and 137 are three of the favourites. Featuring Professor Laurence Eaves. 
 Lottery The chance of picking the six winning numbers from the 49 balls in the UK National Lottery is one in 13,983,816  on the other hand, the odds of selecting no balls??? Featuring James Clewett. 
 Synesthesia Do you see numbers as colours? Featuring Alex Dainis. 
 41337 Kleibers Law The fraction three quarters has a particular interest to biologists because of its link to the research of Max Kleiber and metabolic rates in animals. Featuring Thomas Woolley. 
 Truncated Icosahedron The 32sided truncated icosahedron forms the basis of many footballs (soccer balls!). It's also a big deal in chemistry. Featuring James Grime. 
 Alex Bellos Author Alex Bellos tells us how he wrote a bestselling book about numbers. Featuring Alex Bellos. 
 14 and Shakespeare's Sonnets Poetry and numbers are more closely linked than you may think, citing Shakespeare's 14line sonnets and iambic pentameter as examples. Featuring Roger Bowley. 
 31 Mersenne Prime 3435 is Matt Parker's "ex" favourite number  but they are still on good terms. Featuring Matt Parker. 
 Hexadecimal Did you know "f" is an important number to computer? Featuring James Clewett. 
 16 We discuss the number 16  a perfect square  and how sitting at table 16 led to something bigger.
Featuring Dr Ria Symonds and Matt Parker. 
 Sunflowers
Planting sunflowers in the interests of number research and the memory of Alan Turing.
Featuring James Grime. 
 11
All about number 11, marking the last binary day of a generation: 11.11.11. Also CD error correction and detection.
Featuring James Grime. 