- Use at least two functions --- main() and calculation().

- Remember to call the main function very last.

- Input and output should happen in the main function. Call and pass variables into the calculation function from within the main function, be sure to return the answer back to the main function into another variable.

USE PYTHON

1. A farmer is counting his cows. As the trucks bring them down from lower pasture, they are unloaded into a counting barn. After he enters the total from each truck, ask him if there is another truck to enter. How many cows does he have? (Use a while loop)