# Factors

## The Role of Factors in Everyday Problem Solving

Cheryl wants to decorate her room with 24 printed photos of her loved ones, but realizes that arranging them horizontally on one wall is not an option. She then tries various arrangements, but finally settles on four lines of six photos each, which fit perfectly. This is a prime example of how factors play a crucial role in solving everyday problems. Let's delve deeper into the concept of factors and how they can aid us in our daily lives.

## What are Factors?

Factors are numbers that, when multiplied together, result in a given number. For instance, the factors of 24 are 1, 2, 3, 4, 6, 8, 12, and 24, as they can be multiplied together to get 24. In simpler terms, a factor is a number that divides another number without any remainder. For example, all the factors of 24 divide it completely without leaving any remainder.

## Can Factors be Negative Numbers?

Some numbers can have different sets of factors, including negative factors. For instance, the factors of 6 are 1, 2, 3, 6 and also -1, -2, -3, -6. However, for the purpose of this article, we will focus on positive factors only.

## Characteristics of Factors

- There is a limited number of factors for any given number.
- A factor of a number is always less than or equal to itself.
- Every number has at least two factors - 1 and itself (except for 0 and 1).
- Multiplication and division can be used to find factors.

## Find Factors Yourself

Let's take the example of finding the factors of 18. We can write 18 as 1 x 18, 2 x 9, and 3 x 6, giving us the factors 1, 2, 3, 6, 9, and 18. This is one way to find factors. Another method, which we will discuss in the next section, involves leveraging multiplication and division to identify factors.

## Methods to Identify Factors

As mentioned, there are two ways to find factors - multiplication and division. Let's look at both methods in detail.

## Using Multiplication

The first method involves expressing the given number as a product of two numbers. Then, we list down all the numbers involved in these products, which are the factors of the given number. For instance, to find the factors of 27, we can write it as 1 x 27 and 3 x 9, giving us the factors 1, 3, 9, and 27.

## Using Division

The second method is to identify all the whole numbers that are less than or equal to the given number and divide the given number by each of these numbers. The numbers that give a remainder of 0 are the factors of the given number. For example, to find the factors of 5, we'll divide it by 1, 2, 3, and 4, but only 1 and 5 give a remainder of 0, making them the factors of 5.

**In Conclusion,**

Factors are crucial in solving various problems, such as organizing photos on a wall. They are numbers that divide another number without leaving any remainder and have specific characteristics that make them easier to work with. You can find factors using multiplication or division, depending on the given problem. So, the next time you're faced with a problem, remember to consider the factors!

Breaking down a number into its prime factors is known as prime factorisation, which can be done in two ways: the product of two numbers or the product of its prime factors. This process is essential in finding the number of factors of a given number and for solving equations involving exponents.

The factor tree method, commonly used to determine the prime factorisation of a number, helps to simplify the process. This method involves creating a tree-like structure and breaking down the given number into two factors until they can no longer be factored. The resulting numbers are the prime factors of the given number.

## The Factor Tree Method

Here is a step-by-step process for using the factor tree method:

- Write the given number at the top of the factor tree.
- Branch out the number into two factors that divide it evenly.
- Continue branching out each factor into two more factors until they can no longer be factored.
- The resulting numbers are the prime factors of the given number.
- Write the given number as a product of its prime factors in exponent form.

Let's use an example to demonstrate this process.

## Example:

Find the prime factors of 132 using the factor tree method.

## Solution:

The factor tree for 132 is displayed below:

- 132

- 2 x 66

- 2 x 33

- 3 x 11

Therefore, the prime factors of 132 are **2 x 2 x 3 x 11**, or in exponent form **2 ^{2} x 3 x 11**.

## Finding the Number of Factors

To determine the number of factors of a given number using the factor tree method, follow these steps:

- Find the prime factorisation of the number.
- Express this product of primes in exponent form.
- Add 1 to each exponent.
- Multiply the numbers found in Step 3 to get the total number of factors of the given number.

Lets use the previous example to demonstrate this process.

## Example:

Find the number of factors for 132.

## Solution:

Using the previous factorisation, we can express 132 as **2 ^{2} x 3 x 11**. Adding 1 to each exponent, we get

**3 x 2 x 2 = 12**. Therefore, 132 has a total of

**12**factors.

To verify, we can use the multiplication method to write 132 as a product of two numbers:

1 x 132 = 132

2 x 66 = 132

3 x 44 = 132

4 x 33 = 132

6 x 22 = 132

11 x 12 = 132

The factors of 132 are 1, 2, 3, 4, 6, 11, 12, 22, 33, 44, 66, and 132, which totals to **12** factors.

## Finding Common Factors in Mathematics

When comparing two whole numbers, x and y, we may come across a factor that divides both numbers without leaving a remainder. This number is known as the common factor between x and y.

To find the common factors between two numbers, we simply list down the factors of each number in separate rows and check for overlapping factors. The factors that appear in both lists are the common factors.

For example, let's find the common factors between 14 and 21:

- Factors of 14: 1, 2, 7, 14
- Factors of 21: 1, 3, 7, 21

From this list, we see that the common factors are 1 and 7.

In another example, let's find the common factors between 4, 12, and 16:

- Factors of 4: 1, 2, 4
- Factors of 12: 1, 2, 3, 4, 6, 12
- Factors of 16: 1, 2, 4, 8, 16

From this list, we see that the common factors are 1, 2, and 4.

The highest common factor (HCF) is the largest common factor between two or more numbers. It is denoted by the letter a and can be written as HCF(x, y) = a.

## How to Find the HCF of Two Numbers

There are three ways to find the HCF of two numbers:

- The listing factors method
- Prime factorisation
- The division method

Out of these three techniques, the listing factors method is the simplest. We list the factors of each number and determine the common factors. The highest number in the list of common factors is the HCF.

To learn more about the concepts of finding the HCF and the other methods, refer to our article "Highest Common Factor". Let's use the last two examples from our previous section to demonstrate this.

## Example 1:

What is the HCF of 14 and 21?

## Solution:

The factors of 14 are 1, 2, 7, and 14, while the factors of 21 are 1, 3, 7, and 21. The common factors are 1 and 7, and the highest common factor is **7**.

## Example 2:

What is the HCF of 4, 12, and 16?

## Solution:

The factors of 4 are 1, 2, and 4, the factors of 12 are 1, 2, 3, 4, 6, and 12, and the factors of 16 are 1, 2, 4, 8, and 16. The common factors are 1, 2, and 4, and the highest common factor is **4**.

## The Role of Factors in Mathematics

Factors play a crucial role in mathematics, aiding in the solving of ratios, fractions, equations, and recognizing patterns in algebraic expressions. They are a fundamental concept that helps in simplifying mathematical problems.

## Using Factors in Algebra

In algebra, factors are used in working with polynomials, such as factoring expressions and solving equations. For instance, the factors of 3x^{2} are 1, 3, x, 3x, x^{2}, and 3x^{2}. Similarly, the factors of 5xy are 1, 5, x, y, 5x, 5y, xy, and 5xy.

## The Importance of Factors

Finding factors of a number is crucial because it helps in solving various mathematical problems. By understanding factors, one can easily identify common factors and use them to solve equations and simplify expressions in algebra.

## Distinguishing Factors from Multiples

It is essential to distinguish between factors and multiples. While factors are numbers that can divide a given number without leaving a remainder, multiples are numbers that can be divided by a given number. Factors are useful in real-life scenarios, whereas multiples are used in algebraic calculations.

## Key Takeaways: Factors

- A factor is a number that can divide a given number without leaving a remainder.
- Factors are always positive and are finite in number.
- The factor of a number is always less than or equal to the number.
- Every number has at least two factors: 1 and itself.
- Multiplication and division are used to find factors.
- Prime factorization is expressing a number as a product of prime numbers.
- A common factor is a number that divides two numbers without leaving a remainder.
- The highest common factor (HCF) is the largest number that can divide two numbers without leaving a remainder.

## Finding Factors

To find factors, one can list them, use prime factorization, or division. These methods can be applied to any given numbers.

## The Process of Prime Factorization

Prime factorization is a helpful method for finding the factors of a number by expressing it as a product of prime numbers.

## Examples of Factors

If we take the number 20, its factors are 1, 2, 4, 5, 10, and 20, as these numbers can divide 20 evenly without leaving a remainder.

## Application of Factors in Quadratics

Factors are also used in factoring quadratics using the greatest common factor (GCF) method. This involves finding the common factors of the coefficients of the quadratic equation.

## Conclusion

Factors are essential in mathematics, aiding in the solving of various mathematical problems. Understanding factors and their properties can make math problems easier to solve in both real-life situations and algebraic calculations.