en.wikipedia.org/wiki/Real_number

In mathematics, a **real number** is a value that represents a quantity along a line.
The adjective real in this context was introduced in the 17th century by René ...

www.mathsisfun.com/numbers/real-numbers.html

Mathematicians also play with some special numbers that that aren't **Real**
**Numbers**. The **Real Number** Line. The **Real Number** Line is like a geometric line.

virtualnerd.com/pre-algebra/real-numbers-right-triangles/real-and-irrational/define-real-numbers/real-number-definition

Note: **Real numbers** are numbers that can be found on the number line. This
includes both the rational and irrational numbers. This tutorial explains real ...

math.vanderbilt.edu/schectex/courses/thereals

It is true that the **real numbers** are 'points on a line,' but that's not the whole truth.
This web page explains that the **real number** system is a Dedekind-complete ...

www.khanacademy.org/math/algebra-home/alg-intro-to-algebra/alg-irrational-numbers-intro/v/square-roots-and-real-numbers

An old video of Sal where he simplifies square roots in order to determine
whether they represent rational or irrational **numbers**.

mathworld.wolfram.com/RealNumber.html

"Plouffe's Inverter" includes a huge database of 54 million **real numbers** which
are algebraically related to fundamental mathematical constants and functions.

www.ipracticemath.com/learn/realnumber

Math - Learn **real numbers**, Integers, Fractions, Natural numbers, Whole numbers
, Rational and Irrational numbers -iPracticeMath.

whatis.techtarget.com/definition/real-number

A '**real number**' is any element of the set R, which is the union of the set of a
rational numbers and the set of irrational numbers.

www.britannica.com/topic/real-number

**real number**: In mathematics, a quantity that can be expressed as an infinite
decimal expansion. **Real numbers** are used in measurements of continuously ...