A page of the Numeropedia - the Special Encyclopedia of Numbers
... In Arithmetic, 1+1 = 2, in Computer Science, 1+1 = 0, but in Love, 1+1 = 1!
[Astronomy] The number of natural satellites of the planet Mars: Deimos and Phobos.
[Biology] A human body has many 2 organs: hands, arms, thumbs, feet, legs, knees, ankles, eyes (and eyebrows, eyelids…), ears, cheeks, lips, shoulders, lungs, kidneys…
[Biology] Every animal has either 1 horn (called unihorn) or 2 horns, or none.
[Biology] Every camel has either 1 or 2 humps. One-humped camel is called dromedary, two-humped camel is called Bactrian camel.
[Biology] An animal/insect has an even number of legs: 2, 4, 6, 8, 10 or more. Animals/insects having 2 legs: chickens, ducks, birds…
[Biology] The number of pairs of legs per body segment that millipedes have. Centipedes have only one pair of legs per body segment.
[Biology] The number of phalanges (joints) of a thumb and of a big toe: distal phalange (at the end, having nail) and proximal phalange. The other fingers and smaller toes have 3 phalanges (with middle phalange).
[Calendar] 02/02 or 02-02 is the U.S. Groundhog Day. The most famous (maybe in the world) groundhog Punxsutawney Phil, whose full name is “Punxsutawney Phil, Seer of Seers, Sage of Sages, Prognosticator of Prognosticators, and Weather Prophet Extraordinary”.
[Calendar] Daylight Saving Time in the U.S. starts by moving 1 hour ahead at 2 A.M. on the second Sunday of March and ends by moving 1 hour back at 2 A.M. on the first Sunday of November. Before the year 2007, it is between the first Sunday of April until the last Sunday of October.
[Calendar] February’s birthstone is amethyst (for sincerity).
February’s flower is primrose or violet.
February’s full moon is named “Snow Moon”.
February’s full moon is named “Snow Moon”.
[Calendar] The years (from 1000 to 9999) are either written in full 4 digits or last 2 digits.
[Chemistry] The atomic number of Helium (He).
[Chemistry] The number of electrons that can reside in a shell is 2n2, i.e., 2, 8, 18, 32, 50, 72 and 98.
[Education] A 2nd year college or high school student is a sophomore.
[Education] Valedictorian is the top graduate of the entire graduating class of an educational institution, traditionally based on grades and overall GPA. The second-highest graduate is the salutatorian.
[Education] The number of points to which a course’s grade C is transferred, when computing a student’s GPA (general point average) in the popular 4.0-scale GPA system of most schools. A sign +/– may add/subtract .3 or 0.33 to the basic point, depending on schools.
[EECS] The digit represented by the red color by either first 2 bands or the exponent of 10 represented by that color of the 3rd band (i.e. multiplier is 102) in the electronic resistor/capacitor color code.
[EECS] The most basic base used in Computer Science, base-2 or binary base for binary numbers, used only 2 digits: 0 and 1.
[EECS] The number of nibbles in a byte. The number of bytes in a word. A bit is a binary digit, having value 0 or 1. 1 doubleword = 2 words = 4 bytes = 8 nibbles = 32 bits.
[Flag] The number of different sides on the Oregon state flag. A beaver is figured on the back. On the front are “State of Oregon”, a seal and the year “1859”. The only U.S. state flag has 2 sides.
[Flag] The number of countries whose national flags feature a 7-pointed star: Australia and Jordan.
[Flag] The number of countries whose national flags feature a 6-pointed star: Burundi (three 6-pointed red stars outlined in green, arranged in an equitriangle at the center) and Israel (one 6-pointed blue star (or shield) of David or mathematically a regular 6-pointed star polygon or hexagram, at the center).
[Game] The number of Rooks, Knights or Bishops for each player/side in a chess set.
[Game] The number of Gold Generals, Silver Generals, Knights or Lances for each player/side in a Shogi (Japanese chess) set.
[Game] The number of Mandarins (Guards), Elephants (Bishops), Chariots (Rooks), Cannons or Horses (Knights) for each player/side in a Xingqi (Chinese chess) set.
[Language] “Plural” means a quantity equal to or more than 2.
[Language] Prefixes: Duo-, Di-, Dy-, Bi-… and other words: Deuce, Double, Twin, Twice, Pair, Both, Tandem…
[Language] The number of popular/common English words ending with 3 letters “gry”: angry and hungry.
[Language] The number to replace the word “to” or “too” in slang English.
[Language] “Second hand” merchandises mean used or old ones.
[Language] “Two thumbs up” means very good or excellent.
[Library] ISBN-2 is the International Stand nard Book Number code for books published in French (France, Belgium, Canada and Switzerland).
[Library] ISBN-0-02 is the International Standard Book Number for books published by Macmillan Publishing Company.
[Medical] In doctor’s prescription, “bid “ means “twice a day”, “tid” means “three times a day” and “qid”, “four times a day”, from Latin phrases “bis in die”, “ter in die” and “quarter in die”, respectfully.
[Military] A major general is called 2-star general. (U.S. military).
[Money] The relatively rarely-used U.S. $2 bill figures the portrait of the 3rd U.S. President Thomas Jefferson who designed his own home, called Monticello, whose icon was shown on the back of the bill (until discontinued in 1966). The current bill shows 42 people at the signing of the Declaration of Independence in 1776. The Monticello icon however is still on one side of the U.S. nickel.
[Money] The number of nickels in a dime. (U.S. coins).
[Money] The number of quarters in a half dollar coin. (U.S. coins).
[Money] Benjamin Franklin (on $100 bill) and Alexander Hamilton (on $10 bill) are only 2 persons on modern U.S. paper money who was not ever U.S. President.
[Movie] Names of TV shows/series or movies: “You Only Live Twice”, “2 Fast 2 Furious”, “It Takes Two”, “Two Can Play This Game”, “Two Weeks”, “Two Weeks Notice”, “Two Soldiers”, “The Two Jakes”, “The Mirror Has Two Faces”, “2 days in Paris”, “Two Men Went to War”, “Two for the Money”, “Two Lovers” and “Two Tickets to Paradise”.
[Phone] The digit that can be dialed mnemonically by either letter A, B or C on the telephone keypad.
[Phone] The number to key in text messaging on telephone keypad for letter A.
[Theology] Pope Stephen II died only 2 days after his election in 752. His term is the shortest in the Catholics history.
[Theology] The number of words in the shortest sentence in the Holy Bible: John 11:35, “Jesus wept”.
[Theology] Three represents a perfect harmony: the union of unity (one) and diversity (two).
[World] The number of years in a term for 10 non-permanent members of the United Nations Security Council, elected by the General Assembly.
[Zip] The only 2 U.S. Postal Zip Codes starting with 00: Holtsville, New York 00501 and 00544. Coincidentally, the only 2 U.S. Postal Zip Codes starting with 055 are: Andover, Vermont 05501 and 05544.
[Zip] The number of only U.S. states whose Zip Code’s first digit uses 2 different digits: New York (005 and 1) and Texas (7 and 8). Also, Washington, DC (2 and 569nn).
[Zip] The number of letters used for a U.S. state name postal code in a standard U.S. address.
[Library] First 3 digits (000, 001, 002 and 003) in the Dewey Decimal Classification System call numbers for library books in General Knowledge.
2.0, 2.2, 2.4 & 2.7
2.0, 2.2, 2.4 and 2.7(W, KW or MW) are four of standard numerical values for resistors (of tolerance class 5%) between 2 and 3(W, KW or MW). 2.2mF (microfarads) is one of standard numerical values for capacitors.
[Money] U.S. penny is currently made of 97.5% zinc and 2.5% copper, (since 1982).
[Movie] Name of TV show/series or movie: “Two and a Half Man”.
[Trivia] Economic growth between 2.5% and 3.5% is typically viewed as the norm for a healthy economy in the United States.