dynamic defined name

[hala]

i have 12 defined names correspond to year monthes (represented in 12 folders)
in each folder i have workbook with the same name and structure but sure
different data;
i want in new workbook (same structure) to sum same cells from different
monthes (different difined names) due to user choise;
for example : if user entered from 5 to 9;
this means that i need to sum cells from defined names for folders (May,
June, July, August, September)

Please dont help with code, only excel functions

 

[Bob Phillips]

Do you really mean folders (directories) or are you really referring to
other worksheets or tables?