1. Write a program to find the sum of the first n natural numbers, where the value of n is provided by the user.
2. Write a program to find the sum of the cubes of the first n natural numbers where the value of n is provided by the user.
3. Write a program to sum a series of numbers entered by the user. The program should first prompt the user for how many numbers are to be summed. It should then input each of the numbers and print a total sum.