HCF Shortcut Method

If you are preparing for any competition exam, you need to understand that there is a time limit for each exam within which you have to solve respectable amount of question.

In order to stand a chance in cut throat competition, it is important for you to get acquainted with the shortcut method of solving questions.

In this post we will understand how you can easily solve HCF question in limited time using short cut method. I will try to explain this method using example

(01) Find HCF of 20, 28 and 36 using shortcut method

Step 1:
Find the difference between all the numbers given
28-20 = 8
36-28 = 8
36-20 =16

After subtraction, we got three numbers 8, 8 and 16

Step 2:
Select the number which is smallest
So among the number 8, 8 and 16, the smallest number is 8

Step 3:
Now according to the shortcut rule, the factor of smallest number is the HCF.
Find all the factors of the smallest number
Here, factor of number 8 is the HCF.

Factor of 8 can be displayed as
1 * 8
2 * 4

Four numbers are factor of 8 which are 8, 4, 2, 1
Among above four numbers one number is the right answer

Step 4
Finding the right answer among all the factors
a. Let us start with highest number 8
Is 8 the HCF of (20, 28 and 36)
No, as number 8 do not divide 20 fully

b. Is number 4 can be the HCF (20, 28 and 36)
YES!! as number 4 fully divide 20, 28 and 36

we have got our answer, so we do not need to check the other numbers aka 2 and 1

Hence HCF (20, 28, 36) is 4