Here is a list of all our fun facts in alphabetical order!
- All Horses are the Same Color
- All Numbers are Interesting
- Ants on a Stick
- Arclength Surprise
- Are Coins Fair?
- Area of a Circle or Regular Polygon
- Area of a Hyperbolic Wedge
- Area of an Ellipse
- Arrow’s Impossibility Theorem
- Banach-Tarski Paradox
- Behold! the Pythagorean Theorem
- Bike with Square Wheels
- Binary Card Trick
- Birthday Problem
- Borsuk-Ulam Theorem
- Brouwer Fixed Point Theorem
- Buffon Needle Problem
- Calculus Limerick
- Cantor Diagonalization
- Cantor Set
- Chords of a Unit Circle
- Chords of an Ellipse
- Complex Roots Made Visible
- Computability of Real Numbers
- Conic sections
- Connected Sums
- Continuous but Nowhere Differentiable
- Continuum Hypothesis
- Deal or No Deal
- Dedekind Cuts of Rational Numbers
- Derivative Paradox
- Descartes’ Rule of Signs
- Devil’s Staircase
- Difference of Squares
- Dinner Party Problem
- Divisibility by Eleven
- Divisibility by Seven
- Does Order of Addition Matter?
- Domino and Square Tilings
- Dominoes on a Chessboard
- Drunken Walker and Fly
- e is irrational
- Eccentricity of Conics
- Ellipsoidal Paths
- Envy-free Cake Division
- Equidecomposability
- Euler Characteristic
- Euler’s Formula
- Euler’s Product Formula
- Face Derivatives and Computer Vision
- Farmers and Pesky Birds
- Fermat’s Last Theorem
- Fermat’s Little Theorem
- Fibonacci GCD’s, please
- Fibonacci Number Formula
- Finding the N-th digit of Pi
- Football Field
- Formula for Primes?
- Four Color Theorem
- Four Fours Problem
- Fourier Ears Only
- Fractional Dimensions
- Fundamental Group
- Gabriel’s Trumpet
- Gamma Function
- Gaps in Primes
- Goldbach’s Conjecture
- Greedy to Avoid Progressions
- Hailstone Numbers
- Hairy Ball Theorem
- Ham Sandwich Theorem
- High-Dimensional Spheres in Cubes
- Holey Beads
- How GPS Works
- How many Primes?
- How many Rationals?
- Hugging the Equator
- Hyperbolic Geometry
- i to the i is a Real Number
- Impossible Integral?
- Inchworm on a Rubber Rope
- Inductive Tiling
- Irrationality by Infinite Descent
- Isoperimetric Inequality
- Kakeya Needle Problem
- Kaprekar’s Constant
- Klein Bottle
- Koch Snowflake
- Koch Tetrahedron
- Large Counterexample
- Largest Known Primes
- Leapfrog Addition
- Liouville Numbers
- Lucas’ Theorem
- Magic 1089
- Magic Squares, indeed!
- Making History by Card Shuffling
- Making Magic Squares
- Matching Problem
- Math Limerick
- Medical Tests and Bayes’ Theorem
- Memorizing Pi
- Mind-Reading Number Trick
- Misleading Sequence
- Monty Hall Problem
- Morley’s Theorem
- Mug Trick
- Multidimensional Newton’s Method
- Multiplication by 11
- Multiplication by 111
- Multiplying Complementary Pairs
- Music Math Harmony
- Napoleon’s Theorem
- Nine Point Circle
- Odd Numbers in Pascal’s Triangle
- One Equals Zero: Integral Form
- One Equals Zero!
- One, Two, Three, Pi
- Ordinal Numbers
- Pascal’s Triangle
- Pass the Beer
- Perfect Shuffles
- Pi Approximations
- Pick’s Theorem
- Pigeonhole Principle
- Pizza Slices
- Poker Probability Paradox
- Polyhedral Face Vectors
- Powers of Ten in Base Two and Five
- Pretzel Unlinking
- Prime Number Theorem
- Products of Sums of Two Squares
- Projective Planes
- Proof with Words
- Proofs without Words
- Pythagorean Triples
- Quick Square Roots
- Rational Irrational Power
- Rationals Dense but Sparse
- Really Complex Matrices
- Red-Black Card Trick
- Red-Black Pairs Card Trick
- Reflecting on the Hyperbola
- Regular Solids
- Rental Harmony
- Repeating Digits
- Repunit Fun
- Reuleaux Wheel
- Riemann Hypothesis
- Right Double Cone
- Rising Sequences in Card Shuffling
- Risk-Free Betting on Different Beliefs
- Rolling Polygons
- Rubber Bands Stuck on a Torus
- Scrabble Identity
- Seven Shuffles
- Shortest Pythagorean Proof?
- Sierpinski-Mazurkiewicz Paradox
- Sine of (1/55555….)
- Six Degrees of Separation
- Slices of Hanging Cubes
- Sliding Chords
- Social Choice and the Condorcet Paradox
- Space-filling Curves
- Sperner’s Lemma
- Sphere Eversions
- Spherical Bands
- Spherical Geometry
- Spherical Pythagorean Theorem
- Square Root of Two is Irrational
- Squares Ending in 5
- Squaring Numbers between 40 and 60
- Squaring Quickly
- St. Petersburg Paradox
- Successive Differences of Powers
- Sum of Cubes
- Sum of Cubes and Beyond
- Sum of Prime Reciprocals
- Sums of Reciprocal Powers
- Sums of Three and Four Squares
- Sums of Two Squares
- Sums of Two Squares Ways
- Surface Area of a Sphere
- Suspended Rope Trick
- tamreF’s Last Theorem
- Taylor-made Pi
- Tesseract
- Thinned-Out Harmonic Series
- Toggling Light Switches
- Tower of Powers
- Two Envelopes Paradox
- Unbelievable Unlinking
- Van der Waerden Theorem
- Vickrey Auction
- Visual Multiplication with Lines
- Volume of a Ball in N Dimensions
- Volume of a Cone in N Dimensions
- Wallis’ Formula
- Whiffle Ball
- Why an International Date Line?
- Why Does 0.999… = 1?
- Wilson’s Theorem
- Zero to the Zero Power