Features of the least commno multiple

- lcm(a,a) = a - idempotent
- lcm(a,b) = lcm(b,a) - commutativeness
- lcm(a,b) = (a . b) / GCD(a,b) (GCD is the greatest common divisor)

**Usage**

lcm is used, for example, to add or subtract fractions of different denominators, where the denominator of result is the least common multiple of denominators of added or subtracted fractions.

**Instructions:**

Least Common Multiple (labeled as lcm) of several given integers is the smallest positive number that is a multiple of all given integers. A common multiple of two or more integers is a number that is a multiple of each of those integers.

For example: lcm(48,90) = 720

## Example

How much is lcm(10,4)?

**Your answer:**

lcm(10,4) = ________.

## Solution

How much is lcm(10,4)?

**Your answer:**

lcm(10,4) = **20**.