Zero

Zero (0) is a number. It was introduced into mathematics relatively late, during the early 800s in Indian books. Prior mathematical systems, such as the Babylonian or Greek, did not use zero at all, but still succeded quite well for everyday purposes.

The following are some basic rules for dealing with zero. These rules apply for any complex number x, unless otherwise stated.

• Addition: x + 0 = x and 0 + x = x. (That is, 0 is an identity element with respect to addition).
• Subtraction: x - 0 = x and 0 - x = -x.
• Multiplication: x × 0 = 0 and 0 × x = 0.
• Division: Division by 0 is undefined, because 0 has no multiplicative inverse.
• Exponentiation: x⁰ = 1, except that the case x = 0 may be left undefined in some contexts. For all positive x, 0^x = 0.

---

The year zero does not exist. Instead there is a "zero point" in time between the years [1 B.C.]? and 1.