# Q&A: Why is Zero Considered Even?

*Cross-posted from here.*

I’ll provide the definition of “even” and then follow up with two examples, one of which is familiar (demonstrating that $6$ is even) and another of which is the thing being asked about (demonstrating that $0$ is even).

**Definition of Even.** An integer $n$ is *even* if it is divisible by $2$ with no remainder, meaning that it can be written in the form

where $a$ is an integer.

**Familiar Example: $6$ is Even.** The integer $n=6$ can be written as

(i.e., given $n=6,$ choose $a=3$). Therefore, $6$ is even.

**Another Example: $0$ is Even.** The integer $0$ can be written as

(i.e., given $n=0,$ choose $a=0$). Therefore, $0$ is even.