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Everything about Number

Used to count, measure, and label

A number is a mathematical object used to count, measure, order and label. The most basic examples are the natural numbers: 1, 2, 3, 4, 5, and so forth. Individual numbers can be represented in spoken or written language with number words, or with dedicated symbols called numerals; for example, "eleven" is a number word and "11" is the corresponding numeral. As only a limited list of symbols can be memorized, a numeral system is used to represent any number in an organized way. The most common representation is the Hindu–Arabic numeral system, a decimal system which can display any non-negative integer using a combination of ten Arabic numeral symbols called digits. Numerals can be used for counting, for labelling, for ordering, and for codes. In common usage, however, a numeral is not clearly distinguished from the number that it represents. Wikipedia →

🧭 Start here: a 6-step reading path

  1. Read the overview: NumberA 5-minute orientation
  2. Skim a recent paper: Global estimates on the number of persons across the Alzheimer's disease continuumInfluential work since 2022
  3. Pick up a classic book: Essential MathsThe most-reprinted book on the subject
  4. Read the landmark paper: Detecting the number of clusters of individuals using the software structure : a simulation studyCited 19,915 times
  5. Go sideways: List of types of numbersA closely related topic
  6. Go sideways: Positional notationA closely related topic

📖 Definitions

Noun Quantity of countable things.

Noun An abstract entity used to describe quantity.

Noun A numeral: a symbol for a non-negative integer.

Noun An element of one of several sets: natural numbers, integers, rational numbers, real numbers, complex numbers, and sometimes extensions such as hypercomplex numbers, etc.

🗂️ The subject at a glance

  1. History
  2. Main classification
  3. Subclasses of the integers
  4. Subclasses of the complex numbers
  5. Extensions of the concept

🏆 Landmark papers (most cited)

🆕 Influential since 2022

📚 Books worth reading

Ranked by number of editions on Open Library, a rough measure of how lasting a book is.

🔗 Related topics