Integers are whole numbers, including positive numbers, negative numbers, and zero.

...-3, -2, -1, 0, 1, 2, 3...

Integers have unique properties that have always interested mathematicians. For example, anyone who adds, subtracts, or multiplies two integers will always have an integer as the result. However, dividing two integers can result in a non-integer.

Throughout history, integers have been the building blocks for many advances in mathematics. The group-or set-of positive numbers, negative numbers and zero can also be called rational integers. Many think of positive integers as the first system humans developed for counting possessions. Ancient people probably used their fingers or small stones to count whole numbers. Positive integers are also called the counting numbers.

Records 4,000 years old show that Babylonians looked at the properties of positive integers (now thought of as 'pure' arithmetic). Diophantus of Alexandria, Greece, revised the system of algebra first developed by the Babylonians. Under the...