How to find a factor in a number

Author: Louise Ward
Date Of Creation: 4 February 2021
Update Date: 24 June 2024
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Finding factors of a number | Factors and multiples | Pre-Algebra | Khan Academy
Video: Finding factors of a number | Factors and multiples | Pre-Algebra | Khan Academy

Content

If you know how, finding the factors in a number is as simple as counting 1 2 3. But with larger numbers, you can't just count each factor. This is a good trick to be able to find the factors that are in an integer.

Steps

  1. Choose a number. It can be any number, but it's best to start with simpler numbers.
    • For example, choose 72. However, it can also be considered a variable.

  2. Find the prime factor of the selected number. There are many ways to do that, but normally, creating a factor tree is simple. According to number theory, this is an efficient method because every integer (except -1, 0 and 1) has a certain number of prime factors and when multiplied, the product is exactly the same number. Remember that 0 and 1 are not must be prime.
    • 72 is broken down into 2 and 36; 2, 6 and 6; and finally: 2, 2, 3, 2, 3, which equates to 2 * 3.

  3. Take all exponents and add one to each number.
    • In the examples 2 and 3, the exponents are 3 and 2 - adding one to each gives us 4 and 3.
  4. Get the total number of adjusted exponents..
    • 4 x 3 = 12. 72 has 12 factors - 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36 and 72.
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Method 1 of 1: Example

7540

    • Decomposition to prime factors - 25 (29) (13), because x = x, 29, 13, and 5 all have exponents of 1.
    • Add 1 to the exponent. 3, 2, 2, 2.
    • Get the total number of adjusted exponents. The 7540 has 24 factors.
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15802

    • Decomposition to prime factors - 2 (7901).
    • Adjust exponent - 2, 2.
    • Plus. The number 15802 has four factors - 1, 2, 7901, 15802. 7901 is a prime number.
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Advice

  • The reason for adding one to each exponent is because of the power of the number zero. That is, by 2, it is possible to decompose into four power combinations: 2, 2, 2 and 2. You can multiply 2 by 72 and still get 72 because x = 1 (where 0 is a special exception - it's an unspecified case)
  • This article tells you how many factors there are in a number, without showing how to Analyze Some Numbers into Factors.