I have a worksheet with several tables within a sheet. Each table is
dependent on responses from the previous table and new data received. One of
the things i want to be able to see is how many extra entries there are in
the new table that weren't there in the previous table.

So,
column A B C D
row
1 X 1 X 1 (COPIED FROM PREVIOUS TABLE)
2 Y 4 Y 4 (COPIED FROM PREVIOUS TABLE)
3 Z 5 (NEW DATA RECEIVED)
4 A (NEW DATA RECEIVED)
5

How can I show how many more entries there are in column D as compared to
column B bearing in mind that column C has 4 entries not 3 as D has. So,
final answer should be 1. I'm not sure what formula(s) i should be using.
Can you help?