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
| Uppercase | Lowercase | Name |
|---|---|---|
| Α | α | alpha |
| Β | β | beta |
| Γ | γ | gamma |
| Δ | δ | delta |
| Ε | ε | epsilon |
| Ζ | ζ | zeta |
| Η | η | eta |
| Θ | θ | theta |
| Ι | ι | iota |
| Κ | κ | kappa |
| Λ | λ | lambda |
| Μ | μ | mu |
| Ν | ν | nu |
| Ξ | ξ | xi |
| Ο | ο | omicron |
| Π | π | pi |
| Ρ | ρ | rho |
| Σ | σ / ς | sigma |
| Τ | τ | tau |
| Υ | υ | upsilon |
| Φ | φ | phi |
| Χ | χ | chi |
| Ψ | ψ | psi |
| Ω | ω | omega |
Powers of 2
| n | 2^n | Mnemonic |
|---|---|---|
| 0 | 1 | |
| 1 | 2 | |
| 2 | 4 | |
| 3 | 8 | |
| 4 | 16 | |
| 5 | 32 | |
| 6 | 64 | 64 starts with 6 |
| 7 | 128 | |
| 8 | 256 | |
| 9 | 512 | |
| 10 | 1024 | 1024 starts with 10 |
| 20 | 1048576 | ~1 million |
| 30 | 1073741824 | ~1 billion |
| 40 | 1099511627776 | ~1 trillion |
Integer ranges
- Signed: to
- Unsigned: to
| Bits | Min | Max |
|---|---|---|
| i8 | -128 | 127 |
| i16 | -32,768 | 32,767 |
| i32 | -2,147,483,648 | 2,147,483,647 |
| i64 | -9,223,372,036,854,775,808 | 9,223,372,036,854,775,807 |
| u8 | 0 | 255 |
| u16 | 0 | 65,535 |
| u32 | 0 | 4,294,967,295 |
| u64 | 0 | 18,446,744,073,709,551,615 |
Squares and cubes
| Square | Cube | |
|---|---|---|
| 1 | 1 | 1 |
| 2 | 4 | 8 |
| 3 | 9 | 27 |
| 4 | 16 | 64 |
| 5 | 25 | 125 |
| 6 | 36 | 216 |
| 7 | 49 | 343 |
| 8 | 64 | 512 |
| 9 | 81 | 729 |
| 10 | 100 | 1000 |
| 11 | 121 | 1331 |
| 12 | 144 | 1728 |
| 13 | 169 | 2197 |
| 14 | 196 | 2744 |
| 15 | 225 | 3375 |
| 16 | 256 | 4096 |
| 17 | 289 | 4913 |
| 18 | 324 | 5832 |
| 19 | 361 | 6859 |
| 20 | 400 | 8000 |
NATO phonetic alphabet
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
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
| Rank | Name | Description |
|---|---|---|
| 1 | Royal Flush | A, K, Q, J, 10 of the same suit |
| 2 | Straight Flush | Five cards of the same suit, in sequence |
| 3 | Four of a Kind | Four cards of the same rank |
| 4 | Full House | Three of a kind + a pair |
| 5 | Flush | Five cards of the same suit, not in sequence |
| 6 | Straight | Five consecutive cards of different suits |
| 7 | Three of a Kind | Three cards of the same rank |
| 8 | Two Pair | Two cards of one rank + two cards of another rank |
| 9 | One Pair | Two cards of the same rank |
| 10 | High Card | The highest card in the hand |
Misc
- List of TCP and UDP port numbers
- List of HTTP status codes
- List of HTTP header fields
- Alphabet backward: ZYX W VUTS RQ PON MLK JIHG FED CBA