
set theorythe set of numbers including all positive integers starting from 0.
The set of natural numbers, denoted as , includes all positive integers starting from . It is the basic building block of the number system and is used in counting and basic operations. Here’s a representation of the set of natural numbers:
For example, the numbers , , and are all natural numbers, while numbers like , , and are not part of the set of natural numbers.
Historically, the set of natural numbers hasn’t always included so sometimes you’ll see the set written as to indicate the set of all positive integers starting from .
The set of real numbers, denoted as ℝ, includes all rational and irrational numbers. It represents the entire continuum of possible number values from negative infinity to positive infinity.
The set of rational numbers, denoted as ℚ, can be defined by the quotient of two numbers belonging to the set of integers, where the divisor is nonzero.