I have a simple three column spreadsheet: Column 1 is a description; Column 2
is a range of extensions (6700-6749; 6800-6815; etc.); Column 3 is the number
of extensions from column 2, which I manually typed. At the botton of Column
3 I want to sum all of the numbers in Column 3 for which the corresponding
cell in Column 2 is not blank. I am creating a dial plan and know that I do
not have enough extensions, so some of the cells in Column 2 are blank
(meaning I do not yet have those extensions acquired).

Is there a criteria I can use in the SUMIF function that means "IS NOT
BLANK"? I want this formula to sum only the numbers in Column 3 for which I
have typed the range of extensions in Column 2. Thanks in advance for any
help.