How to Factor Out a Number
Here are some step-by-step instructions on how to use the factor tree when looking for the least common multiple or greatest common factor in math.
- Difficulty:
- Moderately Easy
Instructions
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Let's Begin
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1
First write the number you are trying to factor. For this example we will use the number 26.
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2
Next you want to find out what two numbers can be multiplied together to make 26. In this case that would be 2 times 13, which equals 26. Because the number 2 is in its lowest form and the number 13 is not an even number, you would stop here. The factors for the number 26 are 2 and 13.
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3
Factor a larger number, the number 144.
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4
The numbers 2 times 72 equals 144. You can't stop here because 72 is even and can be divided into. You will leave the 2 because it can't be factored anymore.
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5
The numbers 2 times 36 equals 72. Now you have to divide into the 36 because it is even and can be factored out. This would be the numbers 2 times 18. Then you would factor the 18, which would be 2 times 9.
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6
Here you will see that you are left with the number 9, which seems like it can't be factored because it isn't even, which isn't the case. There is a number that can go into the number 9 evenly which is the number 3, so here you will factor 9 as 3 times 3.
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7
After factoring count up how many numbers you have left that can't be factored. In this case you would have 2 times 2 times 2 times 2 times 3 times 3. To check if you are correct, multiply the numbers together: 2 times 2 is 4, then 4 times 2 is 8, then 8 times 2 is 16, then 16 times 3 is 48, then 48 times 3 equals 144 ,which is the number we started out with.
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1
Tips & Warnings
When factoring, you don't always have to use the number 2; it's just a surefire way to be right each time. You can use larger numbers so you won't have to factor as many times.
