Do you struggle with finding the factors of 90 or any number?
You’re not alone. Factor pairs, factor rainbows, factor trees, prime factorization & calculators can all be helpful tools when it comes to finding the factors of a number. But which method is best for you?
Factors are important when it comes to multiplication and division. That’s why I have created this article – to help make learning and understanding factors easier than ever. I want you to feel confident in your skills so that you can tackle any problem head-on.
Read on to learn how to find the factors of 90 and any other number!
What are the factors of 90?
The factors of 90 are 1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 90.
They can be found using a variety of methods either with or without a calculator.
Factor pairs of 90
To find the factor pairs of 90 you can use your calculator or the divisibility tests.
Using your calculator, try dividing 90 by each whole number starting with 1. Then write down the answer with the divisor as a factor pair.
If the answer is not a whole number then it isn’t a factor.
Here are the factor pairs of 90.
1 x 90 = 90
2 x 45 = 90
3 x 30 = 90
5 x 18 = 90
6 x 15 = 90
9 x 10 = 90
Once you get to 2 consecutive factors like 9 & 10 you know you have found all the factor pairs.
Factor Rainbows
Another way to find factor pairs is to draw a factor rainbow.
To watch how I created this factor rainbow for 90 watch this video.
Prime Factorization of 90
Draw a factor tree to find the prime factors of 90.
There are multiple ways to draw a factor tree for 90 but no matter how you draw it you will always end up with the same prime factors.
Here is a factor tree:
Here is another factor tree. Notice how they both have the same prime factors.
So we can write 90 as a product of prime factors like this:
90 = 2 x 3 x 3 x 5
or in index form this is the prime factorization of 90:
Negative Factors of 90
The negative factors of 90 are -1, -2, -3, -5, -6, -9, -10, -15, -18, -30, -45 & -90.
Both factors need to be negative (or both positive) so that the product is positive 90.
FAQs
What are all the prime factors of 90?
The prime factors of 90 are 2, 3 & 5. They can be found be drawing a factor tree like the ones in this article.
What two numbers make 90?
There are 6 pairs of 2 numbers that make 90.
1 & 90
2 & 45
3 & 30
5 & 18
6 & 15
9 & 10
Final thoughts on the Factors of 90
In this article, we looked at different methods for finding the factors of 90. We started with a method that used division and your calculator, then moved onto factor pairs and factor rainbows that used multiplication and finally looked at factor trees and prime factorization.
Each of these methods has its own benefits and drawbacks, so it is important to understand when each one should be used. Practice using all these methods so that you can become comfortable with them and choose the best one for the given situation.
