<P> In arithmetic and number theory, the least common multiple, lowest common multiple, or smallest common multiple of two integers a and b, usually denoted by LCM (a, b), is the smallest positive integer that is divisible by both a and b . Since division of integers by zero is undefined, this definition has meaning only if a and b are both different from zero . However, some authors define lcm (a, 0) as 0 for all a, which is the result of taking the lcm to be the least upper bound in the lattice of divisibility . </P> <P> The LCM is the "lowest common denominator" (LCD) that can be used before fractions can be added, subtracted or compared . The LCM of more than two integers is also well - defined: it is the smallest positive integer that is divisible by each of them . </P>

What is the meaning of least common multiple