Question

When to use the HCF and LCM in word problems?

Answer 1

Least Common Multiple, also called LCM is that smallest number which is completely divisible by a given set of numbers. For example, 30 is completely divisible by 5, 10 & 15 and hence is the LCM of 5,10 & 15. There is no number less than 30 that can boast the same.

So, whenever you are required to find a number that is divisible by more than one number, you have to find LCM.

Highest Common Factor, also called HCF, is that highest number that completely dividesa given set of number. For example, 25 divides 50, 75, 100, 125, 725, 950. Since there is NO number greater than 25 that divides the given set of numbers, we call 25 as the Highest Common Factor or HCF.

So, whenever you are required to find a number that completely divides more than one number, you have to find HCF.
hope it helps u:-)