Math Trivia: Sets

A set is simply a collection of objects.
We represent common sets by scripted letters.
For example:

R is the set of all real numbers.
N is the set of all natural numbers. That is: N = { 1, 2, 3, ... }
C is the set of all complex numbers.

So far, the symbols make sense. R for Reals, N for Naturals. But what about the following sets?

Z is the set of all integers. Z = {..., -2, -1, 0, 1, 2, ... }
Q is the set of all rational numbers. Formally: Q = { p/q | p, q ∈ Z }

Most readers should be fairly perplexed by the unusual choice of symbols. Why Z and Q? After much delay, here is your math tip:

• The set of all integers is denoted by Z for the german word for integers: Zahlen.
• The set of all rationals is denoted by Q for the word Quotient. Rationals are simply quotients of integers.

Read more about set theory here, and here.