An integer (from the Latin integer meaning "whole") is colloquially defined as a number that can be written without a fractional component. In fact, (rational) integers are algebraic integers that are also rational numbers. Integers are a set of both natural numbers and negatives of them including zero. For example, 21, 4, 0, and -2048 are integers, while 9.75, 5+, and root 2 are not. Unlike floating point numbers, integers cannot have decimal places. When two integers are added, subtracted, or multiplied, the result is also an integer. However, when one integer is divided into another, the result may be an integer or a fraction. For example, 6 divided by 3 equals 2, which is an integer, but 6 divided by 4 equals 1.5, which contains a fraction. Decimal numbers may either be rounded or truncated to produce an integer result. Integers are also used to determine an item's location within an array. This chapter provides an introduction to integers, multiplication and division of integers, removal of brackets.