GCF of 40 and 100
GCF of 40 and 100 is the largest possible number that divides 40 and 100 exactly without any remainder. The factors of 40 and 100 are 1, 2, 4, 5, 8, 10, 20, 40 and 1, 2, 4, 5, 10, 20, 25, 50, 100 respectively. There are 3 commonly used methods to find the GCF of 40 and 100  long division, prime factorization, and Euclidean algorithm.
1.  GCF of 40 and 100 
2.  List of Methods 
3.  Solved Examples 
4.  FAQs 
What is GCF of 40 and 100?
Answer: GCF of 40 and 100 is 20.
Explanation:
The GCF of two nonzero integers, x(40) and y(100), is the greatest positive integer m(20) that divides both x(40) and y(100) without any remainder.
Methods to Find GCF of 40 and 100
The methods to find the GCF of 40 and 100 are explained below.
 Prime Factorization Method
 Long Division Method
 Listing Common Factors
GCF of 40 and 100 by Prime Factorization
Prime factorization of 40 and 100 is (2 × 2 × 2 × 5) and (2 × 2 × 5 × 5) respectively. As visible, 40 and 100 have common prime factors. Hence, the GCF of 40 and 100 is 2 × 2 × 5 = 20.
GCF of 40 and 100 by Long Division
GCF of 40 and 100 is the divisor that we get when the remainder becomes 0 after doing long division repeatedly.
 Step 1: Divide 100 (larger number) by 40 (smaller number).
 Step 2: Since the remainder ≠ 0, we will divide the divisor of step 1 (40) by the remainder (20).
 Step 3: Repeat this process until the remainder = 0.
The corresponding divisor (20) is the GCF of 40 and 100.
GCF of 40 and 100 by Listing Common Factors
 Factors of 40: 1, 2, 4, 5, 8, 10, 20, 40
 Factors of 100: 1, 2, 4, 5, 10, 20, 25, 50, 100
There are 6 common factors of 40 and 100, that are 1, 2, 4, 5, 10, and 20. Therefore, the greatest common factor of 40 and 100 is 20.
☛ Also Check:
 GCF of 60 and 96 = 12
 GCF of 34 and 51 = 17
 GCF of 3 and 6 = 3
 GCF of 15 and 24 = 3
 GCF of 16 and 30 = 2
 GCF of 72 and 84 = 12
 GCF of 36 and 48 = 12
GCF of 40 and 100 Examples

Example 1: Find the GCF of 40 and 100, if their LCM is 200.
Solution:
∵ LCM × GCF = 40 × 100
⇒ GCF(40, 100) = (40 × 100)/200 = 20
Therefore, the greatest common factor of 40 and 100 is 20. 
Example 2: Find the greatest number that divides 40 and 100 exactly.
Solution:
The greatest number that divides 40 and 100 exactly is their greatest common factor, i.e. GCF of 40 and 100.
⇒ Factors of 40 and 100: Factors of 40 = 1, 2, 4, 5, 8, 10, 20, 40
 Factors of 100 = 1, 2, 4, 5, 10, 20, 25, 50, 100
Therefore, the GCF of 40 and 100 is 20.

Example 3: The product of two numbers is 4000. If their GCF is 20, what is their LCM?
Solution:
Given: GCF = 20 and product of numbers = 4000
∵ LCM × GCF = product of numbers
⇒ LCM = Product/GCF = 4000/20
Therefore, the LCM is 200.
FAQs on GCF of 40 and 100
What is the GCF of 40 and 100?
The GCF of 40 and 100 is 20. To calculate the GCF of 40 and 100, we need to factor each number (factors of 40 = 1, 2, 4, 5, 8, 10, 20, 40; factors of 100 = 1, 2, 4, 5, 10, 20, 25, 50, 100) and choose the greatest factor that exactly divides both 40 and 100, i.e., 20.
What is the Relation Between LCM and GCF of 40, 100?
The following equation can be used to express the relation between LCM and GCF of 40 and 100, i.e. GCF × LCM = 40 × 100.
How to Find the GCF of 40 and 100 by Prime Factorization?
To find the GCF of 40 and 100, we will find the prime factorization of the given numbers, i.e. 40 = 2 × 2 × 2 × 5; 100 = 2 × 2 × 5 × 5.
⇒ Since 2, 2, 5 are common terms in the prime factorization of 40 and 100. Hence, GCF(40, 100) = 2 × 2 × 5 = 20
☛ What is a Prime Number?
If the GCF of 100 and 40 is 20, Find its LCM.
GCF(100, 40) × LCM(100, 40) = 100 × 40
Since the GCF of 100 and 40 = 20
⇒ 20 × LCM(100, 40) = 4000
Therefore, LCM = 200
☛ Greatest Common Factor Calculator
How to Find the GCF of 40 and 100 by Long Division Method?
To find the GCF of 40, 100 using long division method, 100 is divided by 40. The corresponding divisor (20) when remainder equals 0 is taken as GCF.
What are the Methods to Find GCF of 40 and 100?
There are three commonly used methods to find the GCF of 40 and 100.
 By Listing Common Factors
 By Long Division
 By Prime Factorization
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