
60 interesting facts about Mathematics that will surprise, entertain and educate you.A number is divisible by 9 if the sum of the digits is divisible by 9. The number zero does not have its own Roman numeral Think to yourself 'How I wish I could calculate pi' and then count the letters in each of the words of that sentence. You now have a way of remembering the first seven digits of pi: 3.141592. The first number to contain the letter a is 'one thousand'. See A NUMBER for the discussion behind this fact. The only number to have its letters in alphabetical order is forty. See Alphanumbetical and try to think of other alphanumbetical mathematical words! The numbers on opposite sides of a dice add up to seven. There are more than 64 squares on a chess board. If you count the squares made up of multiple squares there are 204 altogether. There is one 8x8 square, four 7x7 squares, nine 6x6 squares, 16 5x5 squares, 25 4x4 squares, 36 3x3 squares, 49 2x2 squares and 64 1x1 squares. A prime number has exactly two factors. Two is the only even prime number and it is also the only prime number not to contain the letter 'e'. It should take no more than 20 moves to solve a Rubiks cube no matter which of the 43 quintillion possible starting positions you begin with. A dodecahedron has twelve pentagonal sides. A googol is one followed by one hundred zeros. This can be written as: Not many people appreciate (or understand) the mindblowing fact that: Triangles, squares and hexagons are the only regular polygons that tessellate. The equals sign was invented in 1557 by Welsh mathematician Robert Recorde. The word 'equal' is from the Latin word aequalis as meaning uniform, identical, or equal. 111111111 x 111111111 = 12345678987654321.
Eight comes first if all the numbers are arranged alphabetically. What number would come last? More numbers begin with the digit one than any other digit. This result has been found to apply to a wide variety of data sets, including electricity bills, street addresses, stock prices, population numbers, death rates, lengths of rivers and mathematical constants. This fact was famously attributed to physicist Frank Benford, who stated it in 1938, although it had been previously stated by Simon Newcomb in 1881.
42 is the answer to the 'Ultimate Question of Life, the Universe, and Everything' according to 'The Hitchhiker's Guide to the Galaxy' created by Douglas Adams. 18 is the only number that is twice the sum of its digits. Most clocks which have Roman numerals on their face use IIII for four instead of the more familiar IV. There are currently over 7 billion people in the world and the number is growing very quickly. To see just how quickly have a look at our population counter. Any number to the power zero is 1, and zero to any power is 0. The only unanswered question here is what is zero to the power zero? The Fibonacci sequence is a sequence of numbers where each term is the sum of the previous two terms. The first two terms are both one. The ratio of the n^{th} term to the next term gets closer to the golden ratio as n increases. Air France, Iberia, Ryanair, AirTran, Continental Airlines, and Lufthansa don’t have a row 13 on their airlines because they are aware that many of their passengers consider 13 to be an unlucky number. Many office blocks, office buildings and hotels do not have a 13th floor for the same reason. The following three consecutive numbers are the lowest that are divisible by cubes other than 1: The digits of the number are the same as the digits of the power of ten in these cases:
The polar diameter of the Earth is quite close to (within 0.1%) half a billion inches. The first time a digit repeats six times in succession in pi is at the 762nd position where you can find six nines in a row. This is known as the Feynman Point. The term googol (a 1 followed by 100 zeroes) was first used by a 9 year old boy,Milton Sirotta, in 1938. Trivia submitted by Paul Christian Sarmiento, Philippines As weird as it may seem at first glance, f(x) = 1/(x+1) and g(x) = x/(x+1) have the same derivative. Trivia submitted by Shiraz Dagia, Malawi A number if multiply by 11 is just you bring down the last digits add the digit to the number on it's left and bring down the first number. Trivia submitted by Jericho Fernandez, Laguna, Philippines There is a number smaller than 'a thousand' or 'a hundred and one' with the letter a  it is any number like 0.001 or 'one thousandth' which is smaller than 101 or 1000. These decimals can get infinitely smaller so the proper term for the trivia should be that the smallest whole number not just the smallest number. Trivia submitted by QA, Makaben You can remember the value of Pi (3.1415926) by counting each word's letters in Trivia submitted by Ms. Prescott, Trivia improves critical thinking. Trivia submitted by Wisani, Gauteng, South Africa A googolplex is a googol^{a googol}, or (10^{100}) to the power(10^{100}). Trivia submitted by Anonymous, Planet Earth 40 when written in words "forty" is the only number with letters in alphabetical order, while one is the only one with letters in reverse order. Trivia submitted by Dustin Joseph C. Manalo, Bulacan,Philippines The number 0 is originally called cipher. Trivia submitted by Paras, Philipines The billionth digit of Pi (3.1415 ...) is 9. Trivia submitted by Joy, Manila, Philippines What is the correct mathematical name of the division bar in a fraction? The answer is VINCULUM. Trivia submitted by Lovely Tinamisan, Muntinlupa, Philippines The term "jiffy" is an actual unit of time which is the 1/100th of a second. Trivia submitted by Josh Anilov C. Funelas, Manila, Philippines The value of zero was first used by the ancient Indian mathematician Aryabhata. Trivia submitted by Wency Orbina, Philippines 2520 is the smallest number that is divisible by 1,2,3,4,5,6,7,8,9 and 10. Trivia submitted by MathWizard, Phillipines Moving each letter of the word 'yes' 16 places further up the alphabet produces the word 'oui', the French for 'yes'. Trivia submitted by Greg Ross, Futility Closet Fortytwo percent of Slovenian twoyearolds know the number two, while only four percent of English twoyearolds do. Trivia submitted by Francie Diep, Popular Science The word 'twelve' is worth 12 points in Scrabble. . Trivia submitted by Greg Ross, Futility Closet The words 'ace, two, three, four, five, six, seven, eight, nine, ten, jack, queen, king' contain 52 letters. There are 52 cards in a pack (excluding jokers). Trivia submitted by Greg Ross, Futility Closet If you square11111111 the answer would be 123456787654321. (count the number of 1s and that's the middle number). Trivia submitted by Ranz Louie Ricasa, Philippines The polygon with 1000000 sides is called megagon. Trivia submitted by Ranz Louie Ricasa, Philippines 99*99=9801 Trivia submitted by Ranz Louie Ricasa, Philippines If you find the difference between the number of edges and the number of faces of the tetrahedron, cube, octahedron and other solid shapes, the results will always be 2. Trivia submitted by Ranz Louie Ricasa, Olongapo City,Philippines The second hand on a clock is actually the minute hand. Trivia submitted by Will, Northampton, England If you write out pi to two decimal places, backwards it spells “pie”. Trivia submitted by Me, England The Reuleaux Triangle is a shape of constant width, the simplest and best known such curve other than a circle. Trivia submitted by Manuel Henryk Fabunan, Philippines The mathematical name for # (number sign) is octothorpe. Trivia submitted by Kz Fernandez, Philippines Can you find two numbers without a final 0 that have a product of 10, 100, 1000, 10000 etc. Here is a method: Trivia submitted by Ranz Louie Ricasa, Olongapo City,Philippines Did you know there are five hundred and twentyfive thousand, six hundred minutes in a year? This special number is the main 'hook' of the song Seasons of Love written for the musical Rent.
In the year 1514 the German artist Albrecht Dürer created an engraving called Melencolia with a magic square in the background. The image below shows an enlargement of the magic square. The date appears in the bottom row of the magic square. Using consecutive whole numbers and counting rotations and reflections of a given square as being the same there are precisely:
Zero is the number with the most names or synonyms. It is also known as nought, naught, ow, nil, zilch, zip, diddlysquat, love and scratch. Did you know that if you add 429 and 138 the answer is 567?
The calculation contains the digits 1, 2, 3, 4, 5, 6, 7, 8 and 9.
Trivia submitted by April Jean Elumba, University Of Southern Mindanao J and K are the only letters not in any of the numbers when written as words. Trivia submitted by Theo, Using only addition, you can add 8's to get the number 1,000 by: Trivia submitted by Nightshade, Iligan City The word Trivia comes from the Latin meaning three ways (tri is the prefix for three). At a three way junction there would be a signpost giving information about each direction. This information could be called trivia! There are exactly 8! (eight factorial) minutes in four weeks. All ten digit pandigital numbers are divisible by 3 (a pandigital number contains all the digits 0 to 9). King's Cross station in London has a platform zero! It is the longest platform at the station.
The number 2 is the only prime number that doesn't have the letter e in its name. Trivia submitted by Origaminess, Naperville Did you know that rather than (in the UK) having 1p, 2p, 5p etc. coins it would be mathematically more efficient to have 1p, 3p, 11p and 37p coins? Trivia submitted by No Such Thing As A Fish, Podcast There are 385072 ways of arranging the numbers 1  18 in a circle so that the sum of each pair of adjacent numbers is prime. 153, 370, 371 and 407 are the only threedigit numbers equal to the sum of the cubes of their digits. Any four digit number typed by using four calculator keys at the corners of a rectangle is a multiple of eleven. Here's a useful counterintuitive fact: one 18 inch pizza has more 'pizza' than two 12 inch pizzas. Trivia submitted by Fermat's Library via Twitter, The volume of a deeppan pizza with radius Z and depth A is Older people were born longer ago. 142857 is a circular number Trivia submitted by Philip Robinson, New Zealand The Babylonians were using Pythagoras' Theorem over 1,000 years before Pythagoras was born. Trivia submitted by QI, Octothorpe is the another term for the hashtag sign or the no. sign (#). Trivia submitted by Andrew Stevenizer, Philippines 29 is the number of short straight lines needed to make the number 29 when it is written as words: Here is the formula for solving the equation \(ax^2 + bx + c = 0\). 206 is the smallest number that when written in words contains all five vowels exactly once: Did you know that the area of the regular pentagon on the hypotenuse of a rightangled triangle is equal to the sum of the areas of the regular pentagons on the other two sides? A seventh is eleven sevenths of an eleventh. Trivia submitted by Olberjb, Reddit You’ve met the first six primes: Trivia submitted by Chris Smith @aap03102 Twitter, 12 + 3  4 + 5 + 67 + 8 + 9 equals 100. Trivia submitted by Jimmy Horton, England The division slash (/) is called the virgule Trivia submitted by Jimmy Horton, England All odd numbers have a letter e in them. Maths teachers are very good correcting their pupils when they use the letter O name when they really mean nought or zero. It is important to distinguish between letters (as used in algebra) and numbers. There are however exceptions to this rule that have come about by common usage: 8,549,017,632 The division symbol is called obelus. Trivia submitted by Genius Of Sampaguita 20192020, TNHS  Main TWELVE PLUS ONE = ELEVEN PLUS TWO
142,857 × 1 = 142,857 Here are the only temperatures that are prime integers in both Celsius and Fahrenheit:
Trivia submitted by Fermat's Library On Twitter, FORTY FIVE is an anagram of OVER FIFTY! Any six digit number where the first three digits are repeated as the second three digits is always divisible by 7, 11 and 13 Trivia submitted by Kris Tobin, NSW 41 is prime Trivia submitted by Math Nerd 1729, Philippines "A decimal point" is an anagram of "I'm a dot in place". The ratio of the longer to the shorter side of any Asize paper (A3, A4 etc) is equal to the square root of 2. Trivia submitted by Aravind Mahadevan, The number of milliseconds in a day is: Only digits 1,2 and 3 are possible in the look and say sequence. Trivia submitted by Mr Phil, TSS 2519 is the smallest number that is gives remainder which is one less than the divisor for divisors one to ten: Trivia submitted by S.Suresh ( Zoorace), Salem Tamilnadu India, NEVER ODD OR EVEN is a palindrome, i.e. it reads the same back to front. Trivia submitted by Des MacHale, Guardian That's 105 interesting and surprising facts but there could be more! Do you know any mathematical trivia that could be added to this page? Click here to enter your information. 
Equilateral Triangle
Number of sides: 3Angle sum: 180^{o}Interior angle: 60^{o}Exterior angle: 120^{o}
Square
Number of sides: 4Angle sum: 360^{o}Interior angle: 90^{o}Exterior angle: 90^{o}
Pentagon (regular)
Number of sides: 5Angle sum: 540^{o}Interior angle: 108^{o}Exterior angle: 72^{o}
Hexagon (regular)
Number of sides: 6Angle sum: 720^{o}Interior angle: 120^{o}Exterior angle: 60^{o}
Heptagon (regular)
Number of sides: 7Angle sum: 900^{o}Interior angle: 129^{o}Exterior angle: 51^{o}... to the nearest degree.
Octagon (regular)
Number of sides: 8Angle sum: 1080^{o}Interior angle: 135^{o}Exterior angle: 45^{o}
Nonagon (regular)
Number of sides: 9Angle sum: 1260^{o}Interior angle: 140^{o}Exterior angle: 40^{o}
Decagon (regular)
Number of sides: 10Angle sum: 1440^{o}Interior angle: 144^{o}Exterior angle: 36^{o}
Undecagon (regular)
Number of sides: 11Angle sum: 1620^{o}Interior angle: 147^{o}Exterior angle: 33^{o}... to the nearest degree.
Dodecagon (regular)
Number of sides: 12Angle sum: 1800^{o}Interior angle: 150^{o}Exterior angle: 30^{o}
Tridecagon (regular)
Number of sides: 13Angle sum: 1980^{o}Interior angle: 152^{o}Exterior angle: 28^{o}... to the nearest degree.
Tetradecagon (regular)
Number of sides: 14Angle sum: 2160^{o}Interior angle: 154^{o}Exterior angle: 26^{o}... to the nearest degree.
Pentadecagon (regular)
Number of sides: 15Angle sum: 2340^{o}Interior angle: 156^{o}Exterior angle: 24^{o}... to the nearest degree.
Hexadecagon (regular)
Number of sides: 16Angle sum: 2520^{o}Interior angle: 158^{o}Exterior angle: 23^{o}... to the nearest degree.
Heptadecagon (regular)
Number of sides: 17Angle sum: 2700^{o}Interior angle: 159^{o}Exterior angle: 21^{o}... to the nearest degree.
Octadecagon (regular)
Number of sides: 18Angle sum: 2880^{o}Interior angle: 160^{o}Exterior angle: 20^{o}... to the nearest degree.
Enneadecagon (regular)
Number of sides: 19Angle sum: 3060^{o}Interior angle: 161^{o}Exterior angle: 19^{o}... to the nearest degree.
Icosagon (regular)
Number of sides: 20Angle sum: 3240^{o}Interior angle: 162^{o}Exterior angle: 18^{o}... to the nearest degree.
Metric and ImperialApproximate Equivalents
1 mile = 1.6 km1 metre = 39.37 inches1 foot = 30.5 cm1 inch = 2.54 cm1 kg = 2.2 lb1 gallon = 4.5 litres1 litre = 1.75 pints
Metric Prefixes
mega M 1000000 millionkilo k 1000 thousandhecto h 100 hundreddeca da 10 ten1 onedeci d 0.1 tenthcenti c 0.01 hundredthmilli m 0.001 thousandthmicro μ 0.000001 millionth


Four is the only number that has the same number of letters as its meaning
F,O,U,R.