Integers (8.1)

The integers consist of the positive natural numbers (1, 2, 3, …), their negatives (−1, −2, −3, ...) and the number zero. A formal way of stating this: the integers are the only integral domain whose positive elements are well-ordered, and which has order preserved under addition. Like the natural numbers, the integers form a countably infinite set. The set of all integers is usually denoted in mathematics by a boldface Z (or blackboard bold, ), which stands for Zahlen (German for "numbers").