Why and how to teach HCF Highest Common Factor

When do you need to use HCF?

• When you have to divide something into smaller and equal portions or units
• When you are planning a party and want to decide how many people should be invited
• When there are people or things you have arrange in rows  or even in groups

Example 1:

I want to donate pencils and erasers to kids. My sons gave me 72 pencils and 24 erasers that they want me to donate. Since I am a fair person, I need to make packets in such a way the each packet has same number of pencils and erasers. So how many packets will be made with equal number of pencils and erasers? How many pencils and eraser each child will get?

Find the HCF of pencils and erasers. HCF  of 72 and 24 = 24.

That means, I can make 24 packets and give them to 24 kids.

Each packet will contain 72/24 = 3 pencils and 24/24 = 1 eraser.

So here we were grouping pencils and erasers into packets so that each packet has equal number of pencils and eraser.

Example 2: 

As an exam coordinator, I need to arrange 72 boys and 90 girls in a classrooms. I have been told to make all girls rows and all boys rows. Also the number of rows must be equal for boys and girls. What is the highest number of students on one row?

HCF of 72 and 90 = 18

Hence, 18 students can be arranged in one row so that it has only girls or only boys per row.

I can also find out how many rows of girls and boys will be formed.

Girls rows = 90/18 = 5 rows

Boys rows = 72/18 = 4 rows

[tweetthis twitter_handles=”#teaching-in-fun-ways”]Use HCF to arrange people into groups or things into rows[/tweetthis]

[tweetthis twitter_handles=”#teaching-in-fun-ways”]If you wish to teach HCF in real life, make your kids plan food for your guests. [/tweetthis]

This was a very simple example. But, it’s good to start with.

If you want more such simple examples of other math principles, you can ask me in the comment section. I will try to post, whenever, I am explaining them to my sons.

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