Number 20

A page of the Numeropedia - the Special Encyclopedia of Numbers

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[Biology]  The number of “baby teeth” or “milk teeth” for a child.

 

[Science]  The minimum sound frequency (Hz, Hertz) that a normal human ear can hear. Normal hearing frequency range is 20-20,000 Hz, most sensitive 1000-4000 Hz.

 

[Calendar]  The 20th century is the first century, following the adoption of the current Gregorian calendar, created by Pope Gregory XIII in 1582 to reform the old Julian calendar that has 36,525 days since its century year 2000 is a leap year. The 17th, 18th or 19th century had only 36,524 days, as will have the 21st century.

 

[Calendar]  March 20 or 21 is the Spring Equinox day: Spring begins; day and night are equal lengths.

 June 20 or 21 is Summer Solstice day: Summer begins; the Sun is farthest north of the Equator.

 

[Chemistry]  The atomic number of Calcium (Ca).


[EECS]  The tolerance (20 %) represented when the tolerance (4th) band in the electronic resistor/capacitor color code has no color or black for capacitor only. (Gold 5%; Silver 10%).

 

[EECS]  20(W, KW or MW) is one of standard numerical values for resistors (of tolerance class 5%). 20pF (picofarads) is one of standard numerical values for capacitors.

 

[Flag]  The number of different designs of the U.S. national flag since the country was formed in 4 July 1776. The current 50-star flag made official debut at Independence Hall, Philadelphia on 4 July 1960. The 50th state is Hawaii, proclaimed on 21 August 1959.

 

[Game]  Jigsaw puzzles are typically comprised of 10, 20, 50, 100, 200, 300, 500, 750, 1000, 1500 or 2000 interlocking pieces.

 

[Geology]  I-20, the shortest major U.S. West-East interstate highway, connecting Kent, Texas to Florence, South Carolina, 1536 miles.

 

[Geology]  The number of countries on the world having exactly one bordering country: Brunei (by Malaysia), Canada (by the U.S.), Cuba (by the U.S. Naval Base, Guantanamo Bay), Denmark (by Germany), Dominican Republic (by Haiti), East Timor (by Indonesia), The Gambia (by Senegal), Gibraltar (by Spain), Guadeloupe (by Netherlands Antilles), Haiti (by Dominican Republic), The Holy See/Vatican City (by Italy), Ireland (by United Kingdom), South Korea (by North Korea), Lesotho (by South Africa), Monaco (by France), Papua New Guinea (by Indonesia), Portugal (by Spain), Qatar (by Saudi Arabia), San Marino (by Italy) and United Kingdom (by Ireland).

 

[History]  Mississippi became the 20th state of the U.S. on 10 December 1817.

 

[History]  The 20th U.S. President: James Abram Garfield (Republican, Ohio, March-September 1881).

His Vice President, Chester Alan Arthur (Vermont, 1881), was the 20th U.S. Vice President.

 

[Language]  Prefixes : Icos-, Icosa-, Vice-, Vige-...

 

[Language]  The number of letters in the Filipino alphabet: 5 vowels and 15 consonants: A, B, K, D, E, G, H, I, L, M, N, NG, O, P, R, S, T, U, W and Y. (No letters: C, F, J, Q, V, X and Z).

  

[Math.]  The smallest number whose cube is the sum of 4 consecutive cube numbers: 203 = 8000 = 113+123+133+143.

 

[Math.]  202 = 400 = 70+71+72+73The only other case: 112 = 121 = 30+31+32+33+34.

 

[Math.]  (Sequence of numbers 49…950…0 and 50…050…0)

2025 = (20+25)2 = 452 and 3025 = (30+25)2 = 552 and 45+55 = 100.

 

[Math.]  The 2nd square number that is the sum of squares of 2 consecutive numbers: 841 = 292 = 202+212. Each root number in the series is 6 times the previous root number minus the earlier root number: 1, 52, 292, 1692, 9852

Or in other words:  (20, 21, 29) is the 2nd Pythagorean triple (lengths of 3 sides of a right triangle), where 2 sides are consecutive integers.

 

[Math.]  The Mayan arithmetic system used base-20 or vigesimal system, instead of base-10.

 

[Math.]  The number of non-abelian groups of order less than 20.

 

[Measure]  The number of quires in a ream of paper.

 

[Measure]  The number of pennyweights in a troy ounce.

Units for precious metals weight measures: 1 troy pound = 12 troy ounces = 240 pennyweights = 5760 grains = 373 g (grams).

 

[Measure]  The number of fluidounces in a pint. British imperial units for dry and liquid measures: 1 bushel = 4 pecks = 8 gallons = 32 quarts = 64 pints = 256 gills = 1280 fluidounces = 36.368736 liters.

 

[Measure]  One of popular volumes (fluid ounces or 591 milliliters) of a soft drink bottle.

 

[Measure]  1 long ton (or gross ton) = 20 long (gross) hundredweights = 2,240 lb (pounds) = 1016.0469 kg (kilograms).

1 short ton = 20 hundredweights = 2,000 lb (pounds) = 907.1847 kg (kilograms).

 

[Measure]  1 scruple = 20 grains.

1 pound apothecaries = 12 ounces apothecaries = 96 drams apothecaries = 288 scruples = 5760 grains.

 

[Measure]  The number of pharmacist’s drops in one milliliter.

Commercially: 1 fluid ounce = 576 drops, 1 drop = 0.051 ml and a pharmacist’s drop is rounded to exactly 0.05 ml. Then 1 fluid ounce = 591.5 pharmacist’s drops.

 

[Money]  The number of nickels in one-dollar coin or bill. (U.S. currency).

 

[Money]  A well-known law of economy by Vilfredo Pareto: “80/20”; simply said as: the 20% of a population produces 80% of the population’s outcome.

 

[Money]  The U.S. $20 bill figures the portrait of the 7th U.S. President Andrew Jackson. On the back is the White House.

 

[Movie]  Names of TV shows/series or movies: “20/20” and “Twenty Good Years”.

[Phone]  International telephone dialing code for Egypt.

 

[Science]  One of seven magic numbers in nuclear physics: 2, 8, 20, 28, 50, 82 and 126. They are the numbers of nucleons such that they are arranged into complete shells within the atomic nucleus.

 

[Science]  A 20/20 vision (Snellen faction) is a term for normal visual acuity (the clarity or the sharpness of vision), a person can see clearly things, at a distance of 20 feet, that should be normally seen at that distance. It is named after the Dutch ophthalmologist Herman Snellen, who developed the first standard methods for measuring visual acuity.

 

[Sport]  The 20-yard line in the starting line for an offensive team after a touchback in a football game.

 

[Sport]  The number of numbers/sectors around the bull’s-eye (or the maximum number) on a dartboard, numbered from 1-20 in a random sequence.

 

[Sport]  The red zone is within the 20-yard line to the goal line, on each end of an American football field.

 

[Sport]  The total regular playing time of a hockey match is 60 minutes: 3 playing periods, of 20 minutes each.

 

[Tech.]  Pewter is about 80% tin and 20% lead.

 

[Tech.]  The numbers of automobile engine oil SAE viscosity: 20W-20 (-40, -50), 10W-30 (-40) and 5W-20 (-30).

 

[Trivia]  The 20th wedding anniversary is traditionally named china anniversary. Modernly, it may be replaced by platinum (or emerald).

 

[Trivia]  Population on the sign of the town Amboy, California 92304, a popular Hollywood filming location, founded in 1858, on the historic Route 66, even its exact current population may be different. The town was put on “For Sale” in November 2003.

 

[Trivia]  Pack of cigarettes: 10 or 20.

  

[Trivia]  Pack of soft drink cans or bottles: 4, 6, 12, 18, 20, 24, 30 or 36.

 

[Zip]  The values of the US non-denominated first-class postage stamps and later values, for the first ounce, starting 14 September 1975 at 10¢ to 44¢, in May 2009.  

Series

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A

B

C

D

E

F

G

H

 *

 *

 *

 *

 *

Value (¢)

10

13

15

18

20

22

25

29

32

33

34

37

39

41

42

44

 

020

[World]  The ISO country code for Andorra is 020. (ISO-3166)

 

20.1168

[Measure]  The number of meters (20.1168 m) in a chain.

1 mile = 8 furlongs = 80 chains = 5280 feet = 8000 links = 63,360 inches. Chain (or Gunter’s chain or surveyor’s chain) is a unit used in surveying.

 

20.5 

[Money]  The diameter (mm) of a U.S. nickel has been 21.2mm, since 1883. Earlier it was 20.5mm.

 

20.508...

[Sport]  The 3-point line is equally of distance 6.25 m, or 20 feet 6.1 inches in men’s international basketball court.

 

20 [Trivia]  

A 20-word sentence consisting of words in increasing number of letters from 1 to 20. 

1    I

2    DO

3    NOT

4    KNOW

5    WHERE

6    FAMILY

7    DOCTORS

8    ACQUIRED

9    ILLEGIBLY

10   PERPLEXING

11   HANDWRITING,

12   NEVERTHELESS

13   EXTRAORDINARY

14   PHARMACEUTICAL

15   INTELLECTUALITY,

16   COUNTERBALANCING

17   INDECIPHERABILITY

18   TRANSCENDENTALIZES

19   INTERCOMMUNICATIONS

20   IMCOMPREHENSIBLENESS.