Math Open Reference
Math Open Reference: Real Number
Learn about real numbers with this helpful reference tool. Provides a detailed definition and an interactive activity that enhances further explanation. Includes links to related topics.
Other
Chili Math: Basic Number Properties
Overview of the four basic number properties with examples.
University of Utah
University of Utah: The Number System
This site from The University of Utah provides a definition of commonly used numbers including rational numbers, natural numbers, integers, real and complex numbers and more.
Wolfram Research
Wolfram Math World: Trichotomy Law
From Mathworld a site on trichotomy law. This law tells the three posibilities for real numbers in this short definition.
Wikimedia
Wikipedia: Rational Numbers
Learn the definition of rational numbers. You can also look at some examples and properties, plus learn about Egyptian fractions. Links are provided for additional information.
Curated OER
Math Words: Rational Numbers
Mathwords provides a brief description with an easy to read chart that includes all types of real numbers.