Quiz Monkey |

The Greek letter π (transliterated into English as *pi*) is used to denote one of the most famous constants in mathematics: the ratio
between the diameter and circumference of a circle. It's what's known as an irrational number, because it can't be expressed as a ratio
(i.e. a fraction). For this reason, it is impossible to give an exact value for pi; all we can do is give an approximation.

At school we were taught (or we were in my day) that the fraction 22/7, or three and one seventh, gives a close approximation to *pi*. This
is a rational number, because it can be expressed as a ratio, but like pi it can't be written down exactly as a decimal fraction, because its digits
repeat (or recur, as the mathematicians say) *ad infinitum*. It's equal to approximately 3.142857; after this, those six digits (the ones after
the decimal place) recur.

The actual value of *pi*, to 31 decimal places, is 3.1415926535897932384626433832795.

It's always useful to know the first few digits of *pi*, but unless you're a memory expert (in a way that a quizzer isn't necessarily)
you'll probably need a mnemonic.

There are various mnemonics, and most if not all of them involve learning a sentence or verse where the number of letters in each word in turn gives you the requisite digits.

Here's one I learnt from BBC Radio 4's *Brain of Britain*, some years ago, which gives the first eight digits (including the one before
the decimal point):

May I have a large container of coffee? |

This has always been enough for me in any quiz where the subject (of the value of
*pi*) has ever come up.

Mathematicians will notice that it's not strictly correct, because if we were giving the value of *pi* to eight significant figures,
or seven decimal places, the eighth digit should be a 7 and not a 6.

If you'd like to see a mnemonic for more digits of pi, I would refer you to *i before e (except after c)*, by Judy Parkinson
(Michael O'Mara Books Ltd, London, 2007). Subtitled *Old-School Ways to Remember Stuff*, this book is all about mnemonics, and it
gives various examples for *pi* – including one that gives you the 31 digits as above. It stops at 31 because (as Ms. Parkinson
herself points out) the 32nd decimal place is occupied by a zero, which can't easily be covered by the method of counting the number of
letters in words.

You will also find several other mnemonics in Ms. Parkinson's book which I've stolen for this website.

The questions in this section have nothing in common, except that in each case, the answer is a number.

Where a number is followed by an ellipsis (...), this means that the value given here is approximate.

Square root of 0.25 | 0.5 | |

Surfaces on a Mobius strip | 1 | |

Square root of 2 | 1.414... | |

The 'golden ratio' (known to mathematicians as phi) |
1.618... | |

The only even prime number; also the lowest (1 no longer qualifies) | 2 | |

The base of natural logarithms (e) – a.k.a. Euler's number or Napier's constant | 2.71828184... | |

Hearts of an octopus | 3 | |

Spots on the Domino's Pizza logo | ||

Pi (see previous section for more) |
3.1415926535878... | |

Compartments in the stomach of a cow | 4 | |

Horses involved in the bet known as a Yankee | ||

Lines in a clerihew | ||

Arms of a starfish | 5 | |

Halogens (naturally occurring) | ||

Lines in a limerick | ||

Sides of a prism | ||

Number of places (in each of which there may or may not be a dot) in the cell, or grid, used to represent a character in Braille | 6 | |

Pips in the Greenwich Time Signal (the last one is a long one) | ||

Points on a snowflake | ||

Points on the Star of David | ||

Wings of a Seraph | ||

Hills of Rome | 7 | |

Opposite sides of a die add up to | ||

Points on the Statue of Liberty's crown | ||

Sides on a 50p piece | ||

Neutral on the pH scale | 7.0 | |

Bits in a byte (always, in quizzes!) | 8 | |

Corners on a cube | ||

Humans (traditionally) on Noah's Ark | ||

Nails in a horseshoe (normally) | ||

Points on a Maltese Cross | ||

Records allowed on Desert Island Discs | ||

Queen Victoria's children | 9 | |

Gates in the Thames Flood Barrier | 10 | |

Legs on a lobster | ||

Tentacles of a squid | ||

Herbs & spices used in KFC's secret recipe | 11 | |

Confederate states | ||

Branches on the antlers of a male stag (minimum) | 12 | |

Labours of Hercules | ||

Tribes of Israel | ||

Avenues that radiate from the Place Charles de Gaulle (Paris – previously, and sometimes still, known as the Place de l'Etoile) | ||

Baker's dozen | 13 | |

People at the Last Supper | ||

US colonies (states) that declared independence in 1776, and hence stripes on the US flag | ||

Witches in a coven | ||

Enigma variations (Elgar) | 14 | |

Lines in a sonnet | ||

Stations of the Cross | ||

Degrees of longitude in a time zone | 15 | |

People on a jury, in Scotland | ||

Stones per player at the start of a game of Backgammon | ||

Annas in a rupee | 16 | |

Syllables in a haiku | 17 | |

Quires in a ream | 20 | |

Shillings in a guinea (prior to 1971) | 21 | |

Spots on a die | ||

Letters (characters) in the Hebrew alphabet | 22 | |

Pairs of chromosomes in each human cell | 23 | |

Letters in the Greek alphabet | 24 | |

Pieces at the start of a game of draughts | ||

Sheets in a quire | 25 (or 24) | |

Counties in the Republic of Ireland | 26 | |

Cantons in Switzerland | ||

EU member states (the latest to join was Croatia in 2013) | 28 | |

Characters in the Arabian alphabet | ||

Pieces in a set of dominoes | ||

The Chatanooga Choo Choo left on track number | 29 | |

Letters in the Russian alphabet | 31 or 32 | |

Pieces in a chess set | 32 | |

Points of the compass | ||

Boroughs in Greater London (not counting the City of London) | ||

Pods on the London Eye | ||

Numbers on a roulette wheel (European – including French and British) | 37 (0–36) | |

Numbers on a roulette wheel (American) | 38 (0–36, plus 00) | |

Strings on a harp | 46 or 47 | |

Original members (1945) of the United Nations | 50 | |

Countries in the Commonwealth | 53 | |

Small squares on a Rubik cube | 54 (6 x 9) | |

Letters in Llanfairpwllgwyngyllgogeryllwyndrobwyllllantisiliogogogoch | 58 | |

'The Brighton Line' (in what Bob Monkhouse used to call "Bingo lingo") | 59 | |

Squares on a chess (or draughts) board | 64 | |

Cards in a Tarot pack | 78 | |

Small squares (into each of which you write a number) on a Su Doku grid | 81 | |

Keys on a standard piano | 88 | |

The highest number in bingo (standard version) | 90 | |

Theses in Martin Luther's Disputation on the Power and Efficacy of Indulgences (1517) |
95 | |

Room that contains "the worst thing in the world" (i.e. whatever the victim is most afraid
of) in George Orwell's Nineteen Eighty–Four |
101 | |

Floors in the Empire State Building | 102 | |

A supercentenarian is someone who is over ... years old | 110 | |

Emergency phone number, in the EU and several other countries – standardised by the EU Council in 1991, reaffirmed in 2002 | 112 | |

Elements in the Periodic Table (the last four being officially named in 2016) | 118 | |

Tiles in Mah Jongg (Western version) | 144 | |

Hours in a week | 168 (24 x 7) | |

Spots on a set of (double six) dominoes | 168 (21 x 8) | |

Number for the UK's Directory Enquiries service, operated exclusively by British Telecom until 2002 | 192 | |

Pennies in a pound (pre–1971) | 240 | |

Squares on a Scrabble board | 225 (15 x 15) | |

Sheets in a ream | 500 | |

Total of all the numbers on a roulette wheel | 666 | |

Arabian Nights | 1,001 | |

Bytes in a kilobyte | 1,024 (2 ^{10}) | |

Bytes in a megabyte | 1,048,576 (2 ^{20}) |

© Haydn Thompson 2017–21