The study of numbers begins with the natural numbers. The natural numbers
are the whole numbers 1, 2, 3, 4, 5, etc. Early humans most likely created
natural numbers for counting objects and measuring lines. An important part
of early writing are the words representing these natural counting numbers.
The classic ancient cultures, such as the Roman, Greek, Babylonian, and Sumerian
civilizations all developed symbolic representations for natural numbers.
Negative numbers and zero
seemed to appear later in history. The natural numbers consist of all real
rational numbers. Sets
can also describe the natural numbers. They are the set of integers
greater than zero or the set of positive integers.
Unconventionally, zero is sometimes included in the natural numbers. Within
the set of natural numbers the process of addition
and multiplication of two numbers in math equations
will always lead to another natural number. Basic math
functions and higher math functions, such as geometric
and trigonometric functions are also used to affect
numbers.