This article describes how to go from two tables...
...to a table that shows the difference between each corresponding cell:
Requirements
Two tables with matching rows and columns, and a single statistic that you want to use for the calculation.
Method
1. Select your tables.
2. From Properties , copy the names from General > General > Name and paste them somewhere where you can refer to them later.
3. Select Calculation > Custom Code from the toolbar.
4. Click on the page to place the calculation.
5. In the Code panel, add a line of code in the format of
table1_name - table2_name
Below is the code from this example that calculates the difference between the tables:
table.Q5.Brand.Image.this.wave - table.Q5.Brand.Image.last.wave
7. Select this output and go to Appearance > Appearance > Number format in Properties to adjust decimal places and add a percentage sign.