Let's create a table that can store number data. These numbers can then be used to calculate other values.

Ingredients

Guide

1. Insert a Table Data macro and name it "purchaseTable".
   Edit the parameters of the macro so its Initial Rows is 1.
    

2. Inside the Table Data macro, create a table like this:
    

   Item	Unit Price	Quantity	Total Price
   Item	Unit Price	Quantity	Total Price

3. Now insert Text Data, Number Data and Evaluate Data macros into the table, like in the image below:
   
   
   
   For this example, we will give the macros the following names:

   
   
   • Text Data: item
   • Number Data: unitPrice
   • Number Data: quantity
   • Evaluate Data: totalPrice

   
   

4. In the Evaluate Data macro, type the following code:
    

   ${unitPrice} * ${quantity}

   
   The Evaluate Data macro should now look like this:
   
   
   
   

5. Now, underneath the Table Data macro you created in Step 1, create a Hidden Data macro.
    

   The Hidden Data macro is used when you want to enter data that you would rather not show to the reader of the page.

6. In the Hidden Data macro, create 2 Number Data macros and name them "discount" and "tax".
   With each Number Data macro, click Allow Decimal Values.
   It should look something like this:
   
   
   
   
   
7. It's now time to make Scaffolding do some math.
   Let's calculate:
   
   • Net Total (excluding tax and discount)
   • Discount Amount
   • Tax Amount
   • Grand Total (including tax and discount) 

   Create four Evaluate Data macros for each of the values above and give them relevant names, like in the following image:
   
   
   
   

8. For each of these Evaluate Data macros, enter the following in the Display Format properties:

   $ #,##0.00

9. Type in the following codes in the respective Evaluate Data macros:
   
   Net Total

   sumtable("purchaseTable","totalPrice")

   
   

   Discount Amount

   ${netTotal} * ${discount} / 100

   
   

   Tax Amount
   

   ${netTotal} * ${tax} / 100

   
   

   Grand Total
   

   ${netTotal} - ${discAmt} + ${taxAmt}

   
   Your Evaluate Data macros should look something like this:
   
   
   
   

10. Now save the page, and click Edit Contents. Input the values "10" and "0.5" respectively for the Discount percentage and Tax percentage fields.
    
    

11. You will get the desired results.