plzz.....explain!

hcf is the highest common factor. when you write the prime factors of given numbers, whatever comes out as common to all numbers is the hcf.

e.g.

 50=2*5*5

12=2*2*3

18=2+3*3

we see that 2 is common to all, hence 2 is the hcf.

Also remember that if you can't 'see' any factors common in the factorisation, it doesn't mean there's no hcf.

it's 1.

lcm is the least common multiple. A number which a multiple of all given numbers but of all such multiples it's the least.

 e.g.

15=3*5

25=5*5

24=3*2*2*2

(no common factors,

 so hcf =1)

so what you can do is first find the hcf( it's easier), then take the product of the facors and divide it by the hcf

So, here,

 lcm=(3*5)(5*5)(3*2*2*2)/1=15*25*24

 whatever the product, it's the answer.