I have prepare one monthly work hours report.

First I create two excel sheet
One sheet for employees hours entry sheet
Another one sheet for consolidated sheet.
If they enter hours entry sheet then update consolidated automaticaly(becoz I link in 2 sheets)
But my questions I created hours entry sheet in 31 sub entry sheet.
How to easy to combine sheet in simple calculation?
Ex:
01-08-13 to 31-08-13

This is not clear. But you can reference a cell anyplace in a workbook (or even another workbook) within another cell as part of a formula.

So lets say you want to sum the hours in sheetA in sheetB, you could enter a formual in a cell in sheetB like:

=Sum(SheetA!C2:C25)

This would give a total of that range of cells.