A natural number is a number that you would use for counting. The set of natural numbers consists of 1, 2, 3, 4, 5, 6, 7... and can be represented as:

Integers are what most people would consider "common numbers," such as 5, 104, -45, and 90. They do not consist of fractions or decimals and are a subset of rational and real numbers. The set can be represented as:

A noticeable difference between natural numbers and integers is that the set of natural numbers does not have any negative numbers, while the set of integers contains negative numbers. This means that three integers that are not natural numbers could be -1, -2, and -3.