HCF of Three Numbers By Listing Using All Factors By Multiplication

Step A: Find the Factors Using All Factors By Multiplication

Factor Methods
Factors of 12
1
x
12
2
x
6
3
x
4
4
x
3
Factors of 18
1
x
18
2
x
9
3
x
6
6
x
3
Factors of 24
1
x
24
2
x
12
3
x
8
4
x
6
6
x
4

All Factors By Multiplication Help

1. Start from Number 1.
2. Verify multiplication of pairs.
3. It must equal to number.
4. Continue pairing.
5. Until square root of number.
6. These pairs represent all factors.

What is All Factors By Multiplication?

In the multiplication method for finding factors, we identify the pairs of numbers that multiply together to equal the given number. These pairs represent the factors of the number.

Step B: Find the HCF Using Listing

HCF Method
Calculate HCF
Factors of 12:
1
2
3
4
6
12
Factors of 18:
1
2
3
6
9
18
Factors of 24:
1
2
3
4
6
8
12
24

Listing Help

1. List factors of each number.
2. Identify common factors.
3. If no common factors, HCF is 1.
4. Otherwise, select the highest one.

What is Listing?

The listing method for finding the Highest Common Factor or HCF involves listing all factors of each number, including 1 and the number itself. The biggest common factor is the HCF of the given numbers.

Solved Examples

Examples

Example 1: Find the HCF of 6, 20 and 72.
Solution:
Factors of 6 = 1, 2, 3, 6.
Factors of 20 = 1, 2, 4, 5, 10, 20.
Factors of 72 = 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, 72.
Take the highest common factor.
Here, 2 is the highest common factor of 6, 20 and 72.
Therefore, HCF(6, 20, 72) = 2.
Example 2: Find the HCF of 21, 33 and 69.
Solution:
Factors of 21 = 1, 3, 7, 21.
Factors of 33 = 1, 3, 11, 33.
Factors of 69 = 1, 3, 23, 69.
Take the highest common factor.
Here, 3 is the highest common factor of 21, 33 and 69.
Therefore, HCF(21, 33, 69) = 3.
Example 3: Find the HCF of 16, 52 and 56.
Solution:
Factors of 16 = 1, 2, 4, 8, 16.
Factors of 52 = 1, 2, 4, 13, 26, 52.
Factors of 56 = 1, 2, 4, 7, 8, 14, 28, 56.
Take the highest common factor.
Here, 4 is the highest common factor of 16, 52 and 56.
Therefore, HCF(16, 52, 56) = 4.

Exercise

Highest Common Factor (HCF)

What is HCF?

HCF is also known as Highest Common Factor, GCF or GCD. HCF is the largest number that divides each of the given numbers without leaving a remainder.
The HCF formula can be expressed as,
HCF Formula:
HCF = (a × b)/ LCM(a,b)
where, a and b = Two terms
LCM(a, b) = Least common multiple of a and b

How to find HCF?

The Highest common factor or HCF can be found using various methods, such as: Prime Factorization MethodDivision MethodListing MethodLadder MethodExponents MethodVenn Diagram Method

FAQ

What are the steps involved to find HCF?
1. First find factors for each number using all factors by multiplication.
2. Identify common factors that appear in all three numbers.
3. Select the highest factor among them.
4. Verify the HCF by dividing with numbers without leaving a remainder.
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