Question

......................................define zero (0)......................

Answer 1

It is the only integer (and, in fact, the only real number) that is neither negative nor positive. A number which is not zero is said to be nonzero. A root of a function is also sometimes known as "a zero of ." ... Because the number of permutations of 0 elements is 1, (zero factorial) is defined as 1 (Wells 1986, p. 31).