LCM is Least Common Multiple. I remember when my son asked me about it, I too was not really aware of the real usage of LCM. So I thought let me first find out on internet.

So after I Googled I found the real reason of learning LCM. I am very sure we must have learnt the real reason of where LCM should be used in the school days but I guess either I never paid attention or was never explained the real life usage.

So thank fully my son asked me this question, "Why should we learn LCM mom?"

Have you ever watched how beautifully the Diwali lighting glow one after another, few very fast and others slower.

So what time will it be when all the lights glow at one time!

Hmm, that is easy to watch and observe right with 3 or 5 strings of lighting. But what if I asked you the same question for 2000 strings? How will you observe the 2000 strings?

Well that is when you should use LCM. Least Common Multiple of all 2000 string timings.

Say string A = 1 sec, B = 2 sec, C = 3 sec and so on.

So the LCM of all the timings is that time when all the strings will glow at the same time!

So for all strings with timings between 1 to 3 seconds, LCM = 6.

So at the 6th second all the strings will glow together!

Isn't is wonderful to know that LCM is used in real life!

Similarly, when you want to check when will all the planets moving in different orbits at different revolution will come and collide together !

Or when would all the trains running at different speed come and collide together at a junction?

These are the practical daily applications of LCM.

So hail LCM!

abhijeet says

doesn’t make sense and much useful putting this in school curriculum for kids

Seema sunil agarwal says

Thanku so much

Shaima says

Great thanks :))

AK shah says

Thanks for writing the applications. Now I could use this when i teach others. Thanks a million !

Amit Jha says

Awesome explanation of LCM