__maths__>__Divisibility in Whole Numbers__>__Classification of Numbers based on Remainder in Division: Odd-Even and Prime-Composite__### Odd and Even numbers

In this topic, odd and even numbers are introduced.

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Which of the following is a difference between the two groups of numbers `1,3,5,7,...` and `2,4,6,8,...`?

- One group has numbers that are divisible by `2` with remainder 0
- One group has numbers that are not divisible by `2`
- both the above
- both the above

The answer is "both the above"

The group of numbers `1,3,5,7,...` are not divisible by `2` and are called "**odd numbers**".

The group of numbers `2,4,6,8,...` has the same property, that is, they are divisible by `2` and are called "**even numbers**".

Which of the following is a meaning for the word "odd"?

- to join or add
- the quality of being different or strange
- the quality of being different or strange

The answer is "the quality of being different or strange". Note that the odd numbers can be divisible by other numbers or some are not divisible by any numbers (prime). So these numbers are together called odd.

What is the term used to refer to numbers that are not divisible by `2`?

- Pronunciation : Say the answer once

Spelling: Write the answer once

The answer is "odd numbers".

Which of the following is a meaning for the word "even"?

- short form of evening
- the quality of being uniform
- the quality of being uniform

The answer is "the quality of being uniform". Note that the even numbers are all divisible by at-least `2` (not a prime number) and share the uniform characteristics.

What is the term used to refer the numbers that are divisible by `2`?

- Pronunciation : Say the answer once

Spelling: Write the answer once

The answer is "even numbers".

**Even Numbers** : Numbers that are divisible by `2` are the even numbers. **Odd Numbers** : Numbers that are not divisible by `2` are the odd numbers.

Is `131` an odd number of even number?

- odd number
- odd number
- even number

The answer is "odd number"

Is `131+1` an odd number or even number?

- odd number
- even number
- even number

The answer is "even number".

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