I want to create a formula that adds up numbers from one column that if the
value in a different column, same row is a certain value. As an example, if
column A has months and column B has numeric values, I want to add the values
for a certain month. The key is that the months in column A are repeating.
I may have 15 entries of January in Column A and I want to add the values
from Column B that have a corresponding entry in Column A of January. Any
advice on how to do this?

Thanks in advance.