# Highest Common Factor of 17, 21, 42 using Euclid's algorithm

Created By : Jatin Gogia

Reviewed By : Rajasekhar Valipishetty

Last Updated : Apr 06, 2023

HCF Calculator using the Euclid Division Algorithm helps you to find the Highest common factor (HCF) easily for 17, 21, 42 i.e. 1 the largest integer that leaves a remainder zero for all numbers.

HCF of 17, 21, 42 is 1 the largest number which exactly divides all the numbers i.e. where the remainder is zero. Let us get into the working of this example.

Consider we have numbers 17, 21, 42 and we need to find the HCF of these numbers. To do so, we need to choose the largest integer first and then as per Euclid's Division Lemma a = bq + r where 0 ≤ r ≤ b

Highest common factor (HCF) of 17, 21, 42 is 1.

HCF(17, 21, 42) = 1

## HCF of 17, 21, 42 using Euclid's algorithm

Highest common factor or Highest common divisor (hcd) can be calculated by Euclid's algotithm.

HCF of:

Highest common factor (HCF) of 17, 21, 42 is 1. ### Highest Common Factor of 17,21,42 is 1

Step 1: Since 21 > 17, we apply the division lemma to 21 and 17, to get

21 = 17 x 1 + 4

Step 2: Since the reminder 17 ≠ 0, we apply division lemma to 4 and 17, to get

17 = 4 x 4 + 1

Step 3: We consider the new divisor 4 and the new remainder 1, and apply the division lemma to get

4 = 1 x 4 + 0

The remainder has now become zero, so our procedure stops. Since the divisor at this stage is 1, the HCF of 17 and 21 is 1

Notice that 1 = HCF(4,1) = HCF(17,4) = HCF(21,17) .

We can take hcf of as 1st numbers and next number as another number to apply in Euclidean lemma

Step 1: Since 42 > 1, we apply the division lemma to 42 and 1, to get

42 = 1 x 42 + 0

The remainder has now become zero, so our procedure stops. Since the divisor at this stage is 1, the HCF of 1 and 42 is 1

Notice that 1 = HCF(42,1) .

### HCF using Euclid's Algorithm Calculation Examples

Here are some samples of HCF using Euclid's Algorithm calculations.

### Frequently Asked Questions on HCF of 17, 21, 42 using Euclid's Algorithm

1. What is the Euclid division algorithm?

Answer: Euclid's Division Algorithm is a technique to compute the Highest Common Factor (HCF) of given positive integers.

2. what is the HCF of 17, 21, 42?

Answer: HCF of 17, 21, 42 is 1 the largest number that divides all the numbers leaving a remainder zero.

3. How to find HCF of 17, 21, 42 using Euclid's Algorithm?

Answer: For arbitrary numbers 17, 21, 42 apply Euclid’s Division Lemma in succession until you obtain a remainder zero. HCF is the remainder in the last but one step.