# What are odd and even numbers? The ultimate guide

You may have heard lots about odd and even numbers, but what exactly are they? In this blog, we’ll explore this in more detail and look at examples of odd and even numbers from 1 to 100.

## What are odd and even numbers?

Even numbers are divisible by 2, while odd numbers aren’t.

This means that if you divide an even number by 2, you’ll always get a whole number result (e.g. 10/2 = 5). On the other hand, if you divide an odd number by 2, you’ll get a fractional result (e.g. 9/2 = 4.5).

Keeping this rule in mind can be really helpful when it comes to doing things like addition, subtraction, multiplication and division.

In fact, this divisibility rule can be applied to any even or odd number, not just those between 1 and 100!

Ready to test your knowledge? Have a go at our interactive practice questions!

## Odd numbers 1 to 100

1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 81, 83, 85, 87, 89, 91, 93, 95, 97, 99.

## Even numbers 1 to 100

2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100.

## What are the benefits of learning about odd and even numbers?

Knowing whether a number is odd or even can be helpful in lots of situations. For example, when adding or subtracting numbers, you can pair up odd numbers with odd numbers and even numbers with even numbers to make calculations easier.

For multiplication and division questions, you can also use the fact that odd numbers always give odd results when multiplied together, and even numbers always give even results (except 0, which is neutral).

## When do children learn about odd and even numbers?

As outlined in the national curriculum, pupils start to learn about odd and even numbers in Key Stage 1:

“They practise counting as reciting numbers and counting as enumerating objects and counting in 2s, 5s and 10s from different multiples to develop their recognition of patterns in the number system (for example, odd and even numbers).”

## What numbers are both even and odd?

Some numbers are both even and odd. For example, 2 is even, but it’s also odd because it can be divided by 1 and 2.

3 is also both even and odd because it can be divided by 1 and 3. Are you confused? We were too, but re-read the last few sentences until it sinks in!

## Is 0 an even number?

0 is a very special number! It’s neither even nor odd. This is because the result will always be undefined when you divide a number by 0.

## Is 1 an odd number?

Yes, 1 is an odd number (or is it?)! All numbers that aren’t divisible by 2 are odd numbers. This includes 1, 3, 5, 7, 9, 11, 13 and so on.

However! You could say that 1 isn’t an even number or an odd number. This is because when you divide a number by 1, the result will always be the same number. You decide its fate!

## Do all odd numbers have an ‘e’ in them?

How cool is this?! Odd numbers need to end in 1, 3, 5, 7, 9, and as a result, each number has a letter ‘e’. Mind = Blown!

## Are all prime numbers odd?

All prime numbers are odd. This is because a prime number can only be divided by 1 and itself, so the result will always be an odd number.

Some examples of prime numbers are:

3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47.

## Odd and even number activities

There are lots of things that you can do to explore odd and even numbers with your child or pupils.

• You can learn about them by counting different objects
• You can try counting in 2s, 5s, and 10s
• You can explore what happens when you divide odd and even numbers by each other

Finally, you can try some fun activities together with a friend or family member.

### Here are some odd and even number activities that you can try

1. See if you can find any patterns with odd and even numbers

2. Have a competition with a friend or family member to see who can get to 100 first by only adding odd or even numbers

3. See who can make the biggest odd or even number using the digits 1-9

4. Try to find as many different odd and even numbers as you can

5. See if you can make a number sentence using odd and even numbers (e.g. 3+5=8 or 9+1=10)

6. Have a go at the ‘Odd One Out’ game; you’ll need a partner for this. One person thinks of an odd number between 1-100, and the other person has to guess what it is! The guessing person can only ask if the number is odd or even. The person who is thinking of the number can only say ‘yes’ or ‘no’.

7. Try to solve riddles; for example:

I am an odd number. Take away one letter, and I become even. What number am I?

We hope you have fun with these odd and even number activities!

## Conclusion

Even though odd and even numbers seem simple enough, it can be helpful to have a basic understanding of what they are. This knowledge becomes especially helpful when doing things like addition, subtraction, multiplication and division.

We hope you’ve found this article helpful in learning more about these two types of numbers! For even more ways to explore odd and even numbers, don’t forget to download the DoodleMaths app. It’s filled with thousands of fun, interactive exercises – and is proven to boost confidence and ability in maths!

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