There are a lot of different types of numbers in the world. Each number is different than another, yet they may share some common characteristics. To help themselves keep track of and understand the similarities and differences between numbers, mathematicians have developed a grouping system that categorizes and describes numbers based on their characteristics.
Some of the most common groups in the system are:
Natural numbers
Whole numbers
Integers
Rationals
Real numbers
The grouping system is very similar to the concept of grouping in geography in which things are categorized using characteristics that get more and more specific (country, state, county, city, street. . .)
Integers are a special group or category of numbers that:
Consist of the set of numbers: {. . .-4, -3, -2, -1, 0, 1, 2, 3, 4. . .}
Are all positive and negative whole numbers that do not include any fractional or decimal parts
A few things to note here:
There are no fractions or decimals in any part of the numbers.
Negative numbers often represent the idea of being below a standard value.
Zero is an integer.