numbers1

number

an abstract entity that represents a count or measurement

numeral

a symbol or group of symbols, or a word in a natural language that represents a numbers. It differs from a number just as a word differs from the thing it reffers to

(numerical) digit

in mathematics and computer science, it is a symbol used in numerals to represent numbers in positional numeral systems

integers

they consist of the positive natural numbers, their negatives and the number zero; informally known as "whole numbers"

natural numbers

either the positive integers or the non-negative integers

rational numbers

they can be expressed as a ratio of two integers; usually written as the vulgar fraction a/b, where b is not zero

irrational numbers

they just cannot be expressed as a ratio of two integers; an example is pi

real numbers

they can be given an infinite decimal representation

prime numbers/prime

it is a natural number that has exactly two natural divisors, which are 1 and this number itself

parity

this term refers to objects being even or odd

even numbers

they are multiples of 2

odd numbers

they are not multiples of 2