Excel Formula If Statement - in between percentages

Here is what I am trying to do:

I have one column (lets say Column A) of percentages (ranging from 100% to 0%). I have a second column (lets say Column B) with a number 1-10. I want to create a third column which adds together whatever number is in Column B, and the following: If the percentage is 99-90, add 1. If 89-80, add 2. 79-70, add 3. 69-60, add 4. 59-50, add 5. 49-40, add 6. 39-30, add 7. 29-20, add 8. 19-10, add 9. under 10, add 10.

However, I can't seem to write it properly. Any help would be greatly appreciated.