HCF of Three Numbers By Prime Factorization Using Division

Step A: Find the Factors Using Division

Factor Methods
Factors of 12
2
12
12/2=6
2
6
6/2=3
3
3
3/3=1
1
Factors of 18
2
18
18/2=9
3
9
9/3=3
3
3
3/3=1
1
Factors of 24
2
24
24/2=12
2
12
12/2=6
2
6
6/2=3
3
3
3/3=1
1

Division Help

1. Start with the smallest prime.
2. Divide the number by this prime.
3. Write the quotient below.
4. Repeat until the quotient is 1.
5. Confirm using multiplication.

What is Division?

The division method for finding factors begins by dividing the given number by the smallest prime factor like 2, 3,.. This process is repeated with successive primes until the quotient is 1.

Step B: Find the HCF Using Prime Factorization

HCF Method
Calculate HCF
12
=
2
×
2
×
3
18
=
2
×
3
×
3
24
=
2
×
2
×
2
×
3

Prime Factorization Help

1. List the prime factors of numbers
2. Select common prime factors.
3. Multiply selected prime factors.
4. This gives the HCF.

What is Prime Factorization?

The prime factorization method is an effective approach to find the highest common factor or HCF of two or more numbers. The HCF represents the largest number that divides each given number without leaving any remainder.

Solved Examples

Examples

Example 1: Find the HCF of 27, 36 and 45.
Solution:
Prime factorization of 27: 27 = 3, 3, 3
Prime factorization of 36: 36 = 2, 2, 3, 3
Prime factorization of 45: 45 = 3, 3, 5
Take the common prime factors and multiply them together to get HCF.
Therefore, HCF(27, 36, 45) = 9.
Example 2: Find the HCF of 50, 75 and 100.
Solution:
Prime factorization of 50: 50 = 2, 5, 5
Prime factorization of 75: 75 = 3, 5, 5
Prime factorization of 100: 100 = 2, 2, 5, 5
Take the common prime factors and multiply them together to get HCF.
Therefore, HCF(50, 75, 100) = 25.
Example 3: Find the HCF of 72, 96 and 120.
Solution:
Prime factorization of 72: 72 = 2, 2, 2, 3, 3
Prime factorization of 96: 96 = 2, 2, 2, 2, 2, 3
Prime factorization of 120: 120 = 2, 2, 2, 3, 5
Take the common prime factors and multiply them together to get HCF.
Therefore, HCF(72, 96, 120) = 24.

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. Use the division method for prime factorization.
2. List the prime factors of each number.
3. Identify common factors among the three numbers.
4. Multiply the common factors to find the HCF.
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