**Parity is a mathematical term that describes the property of an integer's inclusion in one of two categories: even or odd.**

An integer is even if it is 'evenly divisible' by two and odd if it is not even. For example, 6 is even because there is no remainder when dividing it by 2. By contrast, 3, 5, 7…

**In mathematics, the natural numbers are those used for counting (as in "there are six coins on the table") and ordering (as in "this is the third largest city in the country").**

Some authors begin the natural numbers with 0, corresponding to the non-negative integers 0, 1, 2, 3, ..., whereas others s…