Other
Chili Math: How to Classify Real Numbers
Explains how to classify real numbers and provides numerous examples.
Other
Nearpod: Irrational Numbers
In this lesson on irrational numbers, 8th graders explore how to identify and plot irrational numbers.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Rational / Irrational Numbers
Math Forum response providing methods to prove that between any two numbers there exist a rational and an irrational number.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Definitions of Rational, Irrational
Math Forum definition and explanation of rational and irrational numbers, the definitions of mathematics is also addressed.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: About Rational Numbers
Math Forum response giving a rather thorough overview of rational and irrational numbers, with a brief look at the history of these and other number sets.
Wikimedia
Wikipedia: Irrational Number
At this site from Wikipedia you can learn the definition of an irrational number, then look at examples and explanations of why some numbers are irrational and others are not.
Free Math Help
Free Math Help: Algebra Lesson: Rational Numbers
Learners examine the set of real numbers. The resource includes detailed explanations about rational and irrational numbers. It provides example problems.
Math Is Fun
Math Is Fun: Surds
Do you know what a "surd" is? It's a type of irrational number. The resource consists of examples as well as a brief origin of the term "surd."
ClassFlow
Class Flow: Rational and Irrational Numbers
[Free Registration/Login Required] By the end of the lesson, students will classify numbers into number families to help understand how to distinguish the difference between rational and irrational numbers. Students will demonstrate this...
ClassFlow
Class Flow: Irrational Numbers
[Free Registration/Login Required] Students are introduced to irrational numbers, and the application in various expressions.
Wolfram Research
Wolfram Math World: Square Root
This math site from Mathworld.com explains what a square root is including information on imaginary numbers and many links. This site also addresses the continued fractions of positive real square roots, in particular the square root of...
Purple Math
Purplemath: Number Types
This site explores the different types of numbers: natural numbers, whole numbers, integers, and rational and irrational numbers. Content includes some practice questions.
Math Open Reference
Math Open Reference: Irrational Number
Learn about irrational numbers with this easy reference guide. Provides a detailed definition and examples that enhance further explanation. Provides links to related topics.
Math Open Reference
Math Open Reference: Surd
Learn about a surd with this handy reference guide. Provides a detailed definition and examples that enhance further explanation. Includes links to related topics.
Curated OER
Math Words: Rational Numbers
Mathwords provides a brief description with an easy to read chart that includes all types of real numbers.