Joes Automotive App

Does anyone know how to do the blocks for the Joes Automotive App? It is on page 318 in the book Starting out with App Inventor. Please Help!!

Use the Math Blocks to calculate the total charges for the services.

Oil change is 25; lube is 20; flush is 30 ; then add the tax and parts

TaxCharges—Returns the amount of sales tax, if any. Sales tax is 6% and is
only charged on parts. If the customer purchased services only, no sales tax is
● TotalCharges—Returns the total charges.

The exercise would like you to calculate charges using Procedures. How to define and use Procedures are also described here Defining Procedures and may help you to solve this school problem and Programming Your App to Make Decisions.

A good way to solve this is to draw a diagram on paper showing how you would create this bill manually, then use the logic to create the app.

For example if oil is checked add 25; if lube is checked add 20, if flush is checked add 30; then total them. Similarly, add the other charges and tax (if applicable).

Do I start the block with initialize local variable or one of the check box components?

You can do this without local variables.
You are going to need to place the objects, like check boxes on the screen eventually and when they are checked add the cost of that service/item.

If checkbox1.checked then do something where checkbox1 is one of the services perhaps

You need variables for each charge