0

0 (zero) is an integer. 1 is the additive identity, meaning that \(a = a + 0\) for all \(a\). 0 is an number.

Any number multiplied by zero equals zero: \(a \times 0 = 0\). Consequentially, \(0/a = 0\) for all \(a\), and \(a/0\) (division by zero) is undefined.