Zoo of Numbers: A page created by the Archimedes Laboratory, which is known for posing challenging mental puzzles. This page offers special information on many numbers, including NaN (not a number), i, and a brazillion.
Properties of 17: A website that features facts, symbolism, and history pertaining to the number 17.
The 47 Society: This website is produced by an international group interested in the number 47, which has been described as the random number that shows up most often when numbers appear randomly. It is sometimes called the quintessential random number.
Prime Number Checker: A calculator where users can input any number to discover whether or not it is prime.
Roman Numeral and Date Conversion: A calculator which will take any date and display it in the Gregorian calendar, the Julian calendar, either calendar in Latin, and the Julian calendar in Roman style.
Introducing Runsums: A site run by Ron Knott, a professor of mathematics at the University of Surrey, that explains the concept of the "runsum," or the sum of a run of whole numbers (such as 4 + 5 + 6 = 15).
Calculator Spelling: A list of 251 words that can be spelled on a calculator using numbers only.
World Clock: A page run by mathematician and physicist Peter Russell that provides continuously updated statistics, such as world population, military expenditure, and total users of the Internet.
The MegaPenny Project: A site that presents unique information about pennies. It includes a visualization of a billion pennies.
Googolplex: This site shows a Googolplexian, which is the largest number with a name. It is the number 1 followed by a googolplex of zeros.
CombinationLock.com: A website that features a multitude of free math games. These games challenge the user to find clues and eventually discover the combination to open a lock.
Binary Numeral System: An article hosted by Academic Kids that provides a wealth of information on the binary numeral system. The article explains its history, its representation, and how to do arithmetic using the binary system.
History and Philosophy of Pi: A website by web developer Brian Taylor that presents information and history concerning the number pi. It lists many interesting facts about pi: For instance, if you were to write out pi to one billion decimal places, it would stretch from New York to Kansas.
Vampire Numbers: A website that features vampire numbers, or numbers that can be written as the product of two numbers (called vampire fangs) that contain the same numerals the same number of times as the vampire number. An example would be 1827 = 21 x 87.