Curated OER
Taylor Series: Natural Number
In this calculus worksheet, students apply the Taylor Series to exponential functions based at either zero or one. There are 2 questions with multiple parts.
Stanford University
Stanford Encyclopedia of Philosophy: Gottlob Frege
Good summary of Frege's thought. Some sections are more technical, but the explanation of his philosophy of language and other sections are more readable.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Numbers
Math Forum response to request for information on various number sets. Also defined and discussed are integers, natural numbers, whole numbers, irrational numbers, transcendental numbers, and algebraic numbers.
Wolfram Research
Wolfram Math World: Natural Number
The set of natural numbers is denoted N or Z+. Unfortunately, 0 is sometimes also included in the list of "natural" numbers (Bourbaki 1968, Halmos 1974), and there seems to be no general agreement about whether to include it.
Wikimedia
Wikipedia: Natural Number
Find out exactly what a natural number is and what some of the controversy is over the definition.
CK-12 Foundation
Ck 12: Arithmetic:
[Free Registration/Login may be required to access all resource tools.] Learn how to add integers.
University of Vienna (Austria)
University of Vienna: Number Sets
Interactive assessment (with multiple correct answers) which determines depth of knowledge in rational, natural, and integer numbers.
Other
Interactive Real Analysis: Natural Numbers, Integers, Rationals
A rigorous definition of natural numbers, integers, and rationals numbers, using advanced mathematics language. Contains links to proofs.
Tech Target
Rational Number: A Whatis Definition
A very good and in-depth explanation of what a rational number is.
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.