Why do you need to know about LCM?

Question

I was wondering how come we need to learn LCM (Least Common Multiple) in school?

Answer 1

It helps a lot with fractions and the sort.

Answer 2

good question but we just do

Answer 3

Not sure how old you are but i've just finished A level maths and you use it even there. It is simple but it used with other formula for harder questions and that!kinda like times tables!

Hope i helped!

Answer 4

If we know about LCM, we can add and subtract different fractions with different denominators.

eg.)

1/2 + 2/3

2 = 2

3 = 3

-------------

The LCM of 2 , 3 is:

2 x 3

= 6

1/2 + 2/3

= (1 x 3)/(2 x 3) + (2 x 2)/(3 x 2)

= 3/6 + 4/6

= 7/6

= 1 1/6

= = = = = = = =

If we know about LCM, we can do factorization on algebra.

eg.)

3x^2 + 6x - 15

= 3(x^2 + 2x - 5)

Answer 5

For counting many things!!

Didn't you ever get any problem that sounds like this?

There are three lamps, red, green and blue.

Red light blinks every 5 seconds

Green light blinks every 8 seconds

Blue light blinks every 12 seconds.

Now, the three lamps blink together.

When will the three lamps blink together again?

You use LCM to do this problem. And get the answer 120 seconds.

Answer 6

I think its one of those things you just accept, i mean why do we need to know the line equation of x=5y  

i guess it helps you with multiplacation