en.wikipedia.org/wiki/Real_number

The development of calculus in the 18th century used the entire set of real numbers without having defined them cleanly. The first rigorous definition was published by Georg Cantor in 1871. In 1874, he showed that the set of all real numbers is uncountably infinite but the set of all algebraic numbers is countably infinite.

www.mathsisfun.com/sets/number-types.html

A combination of a real and an imaginary number in the form a + bi, where a and b are real, and i is imaginary. The values a and b can be zero, so the set of real numbers and the set of imaginary numbers are subsets of the set of complex numbers. Examples: 1 + i, 2 - 6i, -5.2i, 4. Read More ->

thinkzone.wlonk.com/Numbers/NumberSets.htm

Complex numbers, such as 2+3i, have the form z = x + iy, where x and y are real numbers. x is called the real part and y is called the imaginary part. The set of complex numbers includes all the other sets of numbers. The real numbers are complex numbers with an imaginary part of zero.

www.sangakoo.com/en/unit/set-of-numbers-real-integer-rational-natural-and...

Set of numbers (Real, integer, rational, natural and irrational numbers) In this unit, we shall give a brief, yet more meaningful introduction to the concepts of sets of numbers, the set of real numbers being the most important, and being denoted by $$\mathbb{R}$$.

en.wikipedia.org/wiki/Russell's_paradox

If R were normal, it would be contained in the set of all normal sets (itself), and therefore be abnormal; on the other hand if R were abnormal, it would not be contained in the set of all normal sets (itself), and therefore be normal. This leads to the conclusion that R is neither normal nor abnormal: Russell's paradox. Formal presentation

www.emathzone.com/tutorials/algebra/sets-of-real-numbers.html

The natural numbers, also called counting numbers or positive integers, are the numbers $$1,2,3,4,5,$$ and so on, obtained by adding $$1$$ over and over again.The set $$\{ 1,2,3,4,5, \cdots \} $$ of all natural numbers is denoted by the symbol $$\mathbb{N}$$.

math.stackexchange.com/questions/489186/prove-that-the-set-of-all-algebraic...

Prove that the set of all algebraic numbers is countable: proof using fundamental theorem of algebra. 0. On algebraic numbers. 2. Show that the set of all algebraic numbers over the field of rationals is countable. Hot Network Questions Why is my if statement always false?

www.thealmightyguru.com/Pointless/BigNumbers.html

Ever wonder what a number with 228 zeros after it is called? No? Well who asked you anyway? Actually, it's called a quinseptuagintillion. Duh! Here is a list of all the big numbers up till the infamous centillion. Just some more incredibly useless trivia for you from TheAlmightyGuru.

www.khanacademy.org/.../cc-8th-irrational-numbers/v/number-sets-2

All we care about is the fact that we were able to represent x, we were able to represent this number, as a fraction. As the ratio of two integers. So the number is also rational. It is also rational. And this technique we did, it doesn't only apply to this number. Any time you have a number that has repeating digits, you could do this.

quizlet.com/59423514/algebra-2-complex-number-operations-vocabulary-flash-cards

The set of all numbers written in the form a + bi, where a and b are real numbers and b is not equal to 0.