2. Even number is another name for positive even number in mathematics. In mathematics, it can be expressed as 2n (n is a positive integer) as opposed to singular. Even numbers must be divisible by 2. It is worth noting that 0 is an even number (in 2002, the International Mathematical Association stipulated that 0 is an even number, and in 2004, China also stipulated that 0 is an even number).

3. Even numbers often appear in the process of language development, meaning "two", "one pair" and "one pair", which are the same forms of words expressing quantity as singular numbers, plural numbers (even most), such as ancient Greek, old English and old Russian.