The application should calculate and display the order amounts and the grand total in Label control as shown in the attached
image. The clear button must clear all text boxes and calculated labels. The exit button must close the window.
Input validation: Make sure the number of units for each package is numeric, and is not negative.
Use the following test data in the attached image to determine if the application is calculation properly.
![1537_VB.png](https://secure.tutorsglobe.com/CMSImages/1537_VB.png)