Positive cardinality: 1, 3,5,7,9, 1 1 3, 15, 17,19,2/kloc-.

Negative cardinality:-1, -3, -5, -7, -9,-1,-13,-15,-17,-/kloc.

Even numbers: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20. (Where the numbers are 2, 4, 6, 8 and 0, they are even numbers.)

Odd number definition

Among integers, numbers that are not divisible by 2 are called odd numbers. In daily life, people usually call positive odd numbers singular, as opposed to even numbers. Odd numbers can be divided into positive and negative odd numbers.

Uniform definition

Definition 1: In an integer, a number divisible by 2 is called an even number.

Definition two: multiples of two are called even numbers.

In decimal system, you can judge whether the number is odd or even by looking at the single digits: 1, 3, 5, 7 and 9 are odd; Numbers with digits 0, 2, 4, 6 and 8 are even numbers.