Monday, January 26, 2009


A common multiple is a number that is a multiple of two or more numbers. The common multiples of 3 and 4 are 0, 12, 24…
The least common multiple (LCM) of two numbers is the smallest number (not zero) that is a multiple of both.

The HCF and LCM of two nos is given. It is possible to find out the two nos uniquely if

Either the sum or the difference between the two nos is known.

We know HCF X LCM = Product of the nos
Given that A-B or A+B is known.
Thus we have 2 equations and two variables, thus the soln can be uniquely determined.

or LCM/HCF = prime no is known.

Then one of the nos = LCM and the other = HCF.

Two numbers are said to be co primes if their HCF is one.