Pick a Number Trivia Quiz

Answer: The number you picked, plus seven

Somehow, calculating sums and the like seems to be more difficult when we see words instead of numbers or an algebraic notation.

The calculation we did was 2(x + 2) - x + 3 = 2x + 4 - x + 3 = x + 7, where x is the number you picked.

Answer: 7

January, March, May, July, August, October and December.

Answer: 34

The series is called the Fibonacci series. Sometimes it's considered to start with 0, 1, 1, etc. The rule is that all numbers, except the first two, are the sum of the two previous numbers: 1+1=2, 1+2=3, 2+3=5, etc. And 13+21=34.

The number series shows up in, e.g., the growth of many plants.

Answer: Four

The pronunciation of the number four in many East Asian languages sounds the same as the word for death. Model numbers of cars and electronic devices are often changed for the Chinese market so they don't contain any fours. Fear of the number four is called Tetraphobia.

In contrast, the number eight is considered very lucky indeed in China. The official start of the Beijing Olympics was on 8/8 2008 at 8:08:08 PM.

Answer: 40

Forty (40) is the only integer which, when written in English, have all letters in alphabetical order.

Answer: 23

Intuitively, this seems to be too low a number to be true. With two people, the chance of them not sharing a birthday is 364/365, or 99.7%. With three people it is (364/365)*(363/365), or 99.2%, and so on. When you get to 23 people, the chance that nobody shares a birthday with anyone else is 49.3%, so the odds of at least two people doing so are 50.7%: better than 50-50. With 35 people, the odds is 81.4%, with 50 people it's 97.0% and with the highest answer option (72) the odds of at least two people sharing a birthday is 99.95%.

Obviously this requires that all birthdays are equally likely, which may not be the case in real life. Parents can plan when in the year their children will be born.

Answer: Arabic numerals

Without the Arabic numerals, it is doubtful if the bank systems and advanced book-keeping could have developed in the following centuries. Try to multiply LXIX with XIV using Roman numerals, if you can! Mathematics and physics also rely on a system like the Arabic numerals. Fibonacci was not the first European to try to promote their use, but he is credited as being the one who succeeded even if it would take some more time for them to become in general use.

Despite their name, Arabic numerals are generally believed to have originated in the Indian subcontinent.

Answer: 2

The definition of a prime number is that it is only divisible by itself and 1. Since all even numbers are divisible by 2, it follows that 2 is the only even prime number.

Answer: The number of muses in Greek mythology

There were nine muses in Greek mythology.

The list of references to seven goes on and on: seventh heaven, the seven seas, seven colors in the rainbow,... When I need to remember the seven deadly sins (common in pub quizzes) I try to recall the murders in the movie "Se7en": there was one for each deadly sin.

The deadly sins are a Christian reference, but the seven wonders of the worlds and having seven days in the week are both examples from earlier cultures.

Answer: Complex numbers

The order of the answer options is as follows: integers, rational numbers, irrational numbers and complex numbers.

Rational numbers are the result of a division of any two integers. Irrational numbers are the ones that cannot be expressed as such a division. A complex number is the sum of one real number (any rational or irrational number) and one imaginary number. An imaginary number, in turn, is any real number multiplied with "i", which is the square root of -1. Complex and imaginary numbers are extremely useful in physics and engineering, but are not needed to count your score on FunTrivia. For that, we need only a very small subset of integers.