Add contents from different workbooks to the Mastersheet

I have been trying to add the contents from the cells in various workbooks based on the month. Each of the workbook is named Mastersheet-21-Jul-17 (the underlined date corresponds to the last Friday which I get by running a macro that adds the date of last Friday after Mastersheet). So I’ll be having about 4 such sheets every month. Each workbook will have only 1 sheet. Could you please suggest a way where, when I select the month from combobox, all the files corresponding to that month will have their contents added and pasted to the Monthsheet?

Could the same be then added again say in months of 4? Eg: Monthsheet-Jan, Monthsheet-Feb, Monthsheet-Mar, Monthsheet-Apr together to form Grp1?

The addition needs to be performed on cells C4:AB50

For Example:

If Cell C4 in MasterSheet-21-Jul-17 contains 12 and Cell C4 in MasterSheet-28-Jul-17 contains 10 then cell C4 in Monthsheet should contain 22. Similarly for other cells across all the workbooks for that month.

Hi MarvinP,

By adding, I mean I want the sum for the cells. Power Query will append all the data from the files to my Monthsheet one after another. That is not what I wanted in here.

But what I wanted was the sum of Cell C4 from Mastersheet-7-Jul-17, Mastersheet-14-Jul-17, Mastersheet-21-Jul-17, Mastersheet-28-Jul-17 reflected on cell C4 of Monthsheet when I have selected the month of July in Combobox1. Similarly for other cells in the range of C4:AB50.

Eg: Cell F8 in Mastersheet-7-Jul-17 contains: 8
Cell F8 in Mastersheet-14-Jul-17 contains: 12
Cell F8 in Mastersheet-21-Jul-17 contains: 3
Cell F8 in Mastersheet-28-Jul-17 contains: 30

Then when I run the macro present in Monthsheet by selecting the month, the cell F8 in MonthSheet should have the value of 53.

The reason I'm after macro is that there are several other macros running in here, so I can run them one after another.