Maths How To with Anita

# What are the prime factors of 8?

Let’s find the prime factors of 8 by first finding the factors of 8.

## What are the factors of 8?

The factors of 8 are 1, 2, 4 & 8.

These are numbers that 8 can be divided by exactly with no remainder.

Out of these factors, the only number that is a prime number is 2.

So the only prime factor of 8 is 2.

## What is the prime factorization of 8?

The prime factorization for 8 can be found by drawing a factor tree.

The prime numbers are circled in red.

Prime numbers have exactly 2 factors, 1 and itself. So 2 is a prime factor of 8.

The prime factorization of 8 is 2 x 2 x 2

## How to find the prime factors of 8

There are 3 ways to find the factors of 8.

• divisibility rules
• calculator
• factor rainbow

### Using a calculator to find the factors of 8

A simple scientific calculator like this Casio can be used to find the factors of 8.

Step 1: Type in 8 ÷ 1. Since this equals a whole number, 8, then 1 is a factor of 8.

Step 2: Type in 8 ÷2. This equals 4 which is a whole number, so both 2 and 4 are factors of 8.

Step 3: Type in 8 ÷ 3. Since this does not equal a whole number, 3 is not a factor of 8.

Of these factors (1, 2 & 4), only 2 is a prime number, so the only prime factor of 8 is 2.

### Drawing a factor a rainbow for 8

A factor rainbow is a nice colourful method for visual learners to see pairs of numbers (factors) that multiply together to equal 8.

Here is a factor rainbow for 8

## What are the factors pairs of 8?

Factor pairs can be found be drawing a factor rainbow.

1 x 8 = 8

and 2 x 4 = 8

There are no more whole numbers between 2 and 4 that are factors of 8.

So the factor pairs of 8 are (1,8) and (2,4).

## What is the product of prime factors of 8?

The prime factorization of 8 is 2 x 2 x 2.

So we can express 8 as a product of prime factors like this:

8 = 2 x 2 x 2

We can write this in index notation like this:

## Negative factors of 8

The negative factors of 8 are -1,-2,-4 & -8.

Both factors need to be negative so that when multiplied the answer is positive 8.

## FAQs

What is the sum of the factors of 8?

1+2+4+8= 15 so the sum of the factors of 8 is 15.