Formula help for creating portfolio valuation

Hello All,

I am trying to find a formula that will solve a problem of calculating net worth of invested amount across different sheets of the same workbook.

I am attaching the rough work book here. In this under invested tab column C should be the "addition of all units allotted till date (column E) * NAV of that month (Column D)" from all the sheets.

I have highlighted the required fields in each tab and have also mentioned manual formula in the cells above C8 under invested tab.

Thanks in advance.

Rushi.