Formula for deleting duplicate text entries

I have a very large spreadsheet of people who teach classes. There are columns that have a teacher ID, class title, day, month, and year and location. There are a number of duplicates in the spreadsheet and I want to be able to compare the day, month, and year for each class for that specific teacher and eliminate any duplicates. I am stuck am wondering if someone could set me in the right direction.

There are numerous ways to do this. One of the easiest is to use the filter or the subtotal feature and count instead of sum. In order to use the subtotal feature, you must have headings or Titles above each column. Then select the entire range of cells (If Active Cell is A1, just press Ctrl + Shift + Right arrow and then Ctrl + Shift + Down arrow). Select Data tab and then Subtotal. Then roll it up. You can also do the same thing using filter.

Thank you! I had totally forgotten about the filter and was trying to figure out IF statement. This works.

Another question on this. What would be the easiest way to determine what rows had been deleted?

If you are using a filter, it would only hide the numbers unless you were selecting the visible cells and then pasting the values only. That is a good question. There is a really easy way to do this in ACCESS. I guess you could create a column and start typing 1, 2, 3, and then highlight and drag down so that every row had a different number. Then when you filter, you could select visible cells and paste the values only providing you the numbers that are not duplicates. With that list of numbers you could do a formula that found the numbers that are not in your list. I know there is an easier way to do this. But I am sure I could find a way.