Maths How To with Anita # The Factors of 91 and how to find them

Do you know what the Factors of 91 are? If not, don’t worry – you’re about to learn!

In this article, we will show you how to find the Factors of 91 using factor pairs, factor trees, the divisibility rules and your calculator.

You will then be able to apply these strategies to find the factors of any number.

## What are the factors of 91?

The factors of 91 are 1, 7, 13 & 91.

These are also known as the positive factors of 91.

## What are the factor pairs of 91?

Factor pairs can be found using a calculator or the divisibility rules.

Divide 91 by each whole number starting at 1. If the answer is a whole number then the divisor and the answer are factor pairs of 91.

e.g 91 divided by 1 = 91

Therefore 1 x 91 = 91

91 can’t be divided by 2 because it doesn’t end in an even number.

91 can’t be divided by 3 because the sum of the digits isn’t divisible by 3.

Try using your calculator for 91 divided by 4. The answer is not a whole number so 4 is not a factor of 91.

91 doesn’t end in a 0 or 5, so it is not divisible by 5.

Since 2 and 3 are not factors of 91, then 6 is also not a factor of 91.

Try using your calculator for 91 divided by 7. The answer is 13. So 7 & 13 are a factor pair of 91.

Now we only have to test the whole numbers between 7 & 13.

Use your calculator to divide 91 by these numbers and you will see there aren’t any more factors.

So the factor pairs of 91 are

1 x 91 = 91

7 x 13 = 91

## Prime Factors of 91

Draw a factor tree to find the prime factors of 91.

The prime factors of 91 are 7 & 13. They are circled in red in the factor tree. They are both prime numbers as they don’t have any other factors besides 1 and themselves.

91 = 7 x 13

## Negative factors of 91

The negative factors of 91 are -1, -7, -13 & -91.

When 2 negative numbers are multiplied together the answer is positive.

So both factors need to be negative to result in a product of positive 91.

## Final Thoughts on finding the factors of 91.

There are many methods to finding the factors of 91. Some people use a calculator, some people use their brain, and others use a little bit of both.

Whichever method you choose, just be sure to practice so that you can get better at it so you’re able to find the factors of any number.

## Further Factors!

Factors of 18

Factors of 30

Prime Factorization of 42

Factors of 50

Factors of 64

Factors of 90

Factors of 91

Factors of 96

Factors of 120