- Zero, 0, is neither positive or negative
- Any real number multiplied by 0 is 0, 0 * n = 0
- 0 divided by any real number other than 0 is 0, \frac { 0 }{ n } =0
- When n is a real number not equal to 0 itself, \frac { n }{ 0 } is undefined
- Anomaly: zero factorial, 0! = 1