The number 30 is even.
A number is even if it is divisible by 2.
The number 30 is even, because it's divisible by 2: the remainder is zero when divided by 2.
How to recognize an even number: its last digit, the one that is in the ones place (the first digit of the number counted from the right) is: 0, 2, 4, 6, or 8.
Mathematically, the even numbers can be written as:
2 × k, where k ∈ Z, the set of integer numbers
Operating rules
When working with even and odd numbers, the following rules apply:
Addition: even + even = even; even + odd = odd; odd + odd = even.
Subtraction: even - even = even; even - odd = odd; odd - odd = even.
Multiplying: even × even = even; even × odd = even; odd × odd = odd.
Other operations of the same kind: