Populating a Duplicate Table as User Enters Data

I have two tables. When the form user clicks the add row button, Table 1 and Table 2 both add a new instance of their respective Row 1.

I am now trying to script so that when the user populates the fields in the first two cells of the new row in Table 1, the same cells in the new row in Table 2 populate automatically so that the tables are identical. I assume I put the script in the change event of the first two cell fields but have to somehow count how many rows have been addded so I know which row to populate.