Can somebody give me a mathematical definition of zero?

Zero is the integer denoted 0 that, when used as a counting number, means that no objects are present. 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 ."

9/12 is the answer because 3/4 times 3 each is 9/12