▸▸▸

Odd Numbers

(KS2, Year 6)

An odd number is a whole number that cannot be divided exactly by 2.

Dictionary Definition

The Oxford English Dictionary defines an even number as a number "having one left over as remainder when divided by two. Opposed to even."

Examples of Odd Numbers

Some examples of odd numbers are given below: list_of_odd_numbers

Odd Numbers on a Number Line

The image below shows the odd numbers on the number line.

odd number line

How to Check if a Number Is an Odd Number

A number is odd if it cannot be divided exactly by 2. If it is divided by 2, the answer will not be a whole number. There will be a remainder of 1.

Question

Is 25 an odd number?

Step-by-Step:

1

Divide the number by 2.

25 ÷ 2 = 12.5 = 12 r 1

2

Check if the answer from Step 1 is a whole number. If it is not, and there is a remainder of 1, the original number is odd. Else it is even. In our example, 12.5 is not a whole number.

Answer:

25 is an odd number.

A Formula to Generate Odd Numbers

The formula below generates odd numbers:

If k takes a whole number (1, 2, 3...), then n will always be odd.

k = 0 ∴ n = 2k + 1 = 2 × 0 + 1 = 1

k = 1 ∴ n = 2k + 1 = 2 × 1 + 1 = 3

k = 2 ∴ n = 2k + 1 = 2 × 2 + 1 = 5

k = 3 ∴ n = 2k + 1 = 2 × 3 + 1 = 7

k = 4 ∴ n = 2k + 1 = 2 × 4 + 1 = 9

Interactive Game on Odd Numbers

Here is an interactive game to help you learn about odd numbers.

You are the fish.
Pop the bubbles with odd to collect points.
Every correct bubble you pop earns you a green tick. If you can get five green ticks, you'll earn 1,000 bonus points! However, when a bubble with an odd number reaches the top without being popped, you will lose a green tick.
Avoid the bubbles with even numbers. If you pop one, you will lose one of your three lives and your green ticks will return to zero.
The lower you pop a correct bubble the more score you score.
Good luck!
The fish moves towards your clicks. (Hint: The farther the distance, the faster it moves.)