What is an even number?

Definition

An integer number is an even number whenever it is divisible by 2.

Otherwise, it is said to be an odd number.

For example, 2 020 is even because it is divisible by 2 since 2 020 = 1 010 × 2 + 0, therefore the remainder is zero (0). Conversely, 2 021 is not divisible by 2 because 2 021 = 1 010 × 2 + 1, hence the remainder is 1, therefore non-zero; as a consequence, 2 021 is an odd number.

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