Zero is the additive identity — adding 0 changes nothing. It also marks an empty count.
Why zero is special
- x + 0 = x for any x.
- x · 0 = 0 for any x.
- 0 / x = 0 (for x ≠ 0).
- x / 0 is undefined.
The Indian mathematician Brahmagupta (628 CE) wrote the first rules for zero as a number.