### Least common multiple (LCM)

Use the greatest common divisor (GCD) formula and `Math.abs()` to determine the least common multiple.
The GCD formula uses recursion.

```js
const lcm = (x,y) => {
  const gcd = (x, y) => !y ? x : gcd(y, x % y);
  return Math.abs(x*y)/(gcd(x,y));
};
// lcm(12,7) -> 84
```