Find and Delete

I have asked this before, the answer I believe unfortunately was wrong after
3 hours of work

I have 7436 Numbers in Col A some of which are duplicated
I wish to delete all the duplicates in Col A including the origanal Numbers.


I have 2300 Numbers in Col B

If a number in Col B appears in Col A I wish to delete that number in Col A

If you can help thanks

in advance

Karen