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Trivia

Last updated: 2 Jan 2020 ·
Posted in wiki#notes

This is a small list of things that feel useful/satisfying to carry around in your head. Sometimes they come in very handy.

Measurements

  • 1 inch = 2.54 cm
  • 1 ft = 12 inch = 30.48 cm
  • 1 mile = 1.609 km
  • 1 oz = 28.34 g
  • 1 gal = 4.54 L
  • 1 US gal = 3.78 L
  • 1 lb = 0.45 kg
  • 1 kg = 2.2 lb
  • 1 tbsp. = 15 ml
  • 1 tsp. = 5 ml
  • 1 hectare = 10000 sq. m (100m x 100m) = 2.47 acres
  • 1 acre = 4046.85 sq. m (66ft x 660ft) ~ 40% of hectare

Greek alphabet

UppercaseLowercaseName
Ααalpha
Ββbeta
Γγgamma
Δδdelta
Εεepsilon
Ζζzeta
Ηηeta
Θθtheta
Ιιiota
Κκkappa
Λλlambda
Μμmu
Ννnu
Ξξxi
Οοomicron
Ππpi
Ρρrho
Σσ / ςsigma
Ττtau
Υυupsilon
Φφphi
Χχchi
Ψψpsi
Ωωomega

Powers of 2

n2^nMnemonic
01
12
24
38
416
532
66464 starts with 6
7128
8256
9512
1010241024 starts with 10
201048576~1 million
301073741824~1 billion
401099511627776~1 trillion

Integer ranges

  • Signed: 2n1-2^{n-1} to 2n112^{n-1}-1
  • Unsigned: 00 to 2n12^n-1
BitsMinMax
i8-128127
i16-32,76832,767
i32-2,147,483,6482,147,483,647
i64-9,223,372,036,854,775,8089,223,372,036,854,775,807
u80255
u16065,535
u3204,294,967,295
u64018,446,744,073,709,551,615

Squares and cubes

SquareCube
111
248
3927
41664
525125
636216
749343
864512
981729
101001000
111211331
121441728
131692197
141962744
152253375
162564096
172894913
183245832
193616859
204008000

NATO phonetic alphabet

[Wikipedia]

Alfa, Bravo, Charlie, Delta, Echo,
Foxtrot, Golf, Hotel, India, Juliett,
Kilo, Lima, Mike, November, Oscar,
Papa, Quebec, Romeo, Sierra, Tango,
Uniform, Victor, Whiskey, Xray, Yankee,
Zulu

SI prefixes

[Wikipedia]

quetta, ronna, yotta, zetta, exa, peta, tera, giga, mega, kilo,
unit (10^0),
milli, micro, nano, pico, femto, atto, zepto, yocto, ronto, quecto

Paper sizes

[International standard paper sizes]

(Aspect ratio of sqrt(2))

  • A0: 841 × 1189 (1 sq. m area)
  • A1: 594 × 841
  • A2: 420 × 594
  • A3: 297 × 420
  • A4: 210 × 297 (1/16 of A0)

Poker

[List of poker hands]

RankNameDescription
1Royal FlushA, K, Q, J, 10 of the same suit
2Straight FlushFive cards of the same suit, in sequence
3Four of a KindFour cards of the same rank
4Full HouseThree of a kind + a pair
5FlushFive cards of the same suit, not in sequence
6StraightFive consecutive cards of different suits
7Three of a KindThree cards of the same rank
8Two PairTwo cards of one rank + two cards of another rank
9One PairTwo cards of the same rank
10High CardThe highest card in the hand

Misc