* Functions * -- do NOT try these recursively, unless you are very brave...
1. Write a function called "lcm" that takes as input two integers, and returns the smallest integer that is divisible by both of them
2. Write a function called "gcd" that takes as input two integers, and returns the largest integer that both of them are divisible by
3. Write a function called "average" that takes as input two integers a and b, and returns the average of the range from a to b (i.e the range a,a+1,a+2,a+3,...b-1,b)
4. Write a function called "isCube" that takes as input an integer, and determines whether it is the cube of another integer (returns a boolean)
5. Write a function called "skipSum" that takes three integers a, b, anb k as input, and returns the sum from a to b, counting by k (i.e. a + (a+k) + (a+2k) + (a+3k) + ... up to b)

* Recursion *
1. Write a function called "product" that takes two integer inputs and returns their product, without using * (i.e. only addition!)