How do I redirect formula links in a duplicated table?

Question

I am putting together an annual accounts spreadsheet in Numbers. I have several worksheets with a set of tables for the first month. The final worksheet contains a summary table which gathers data from across all the tables on the other sheets. No problem so far. But when I create a new set of tables for the second month I also duplicate the summary table. Now all the values are still drawn from the first month tables. How can  I redirect all the formulas to the second set of tables? Is this possible?
If this sounds a bit confusing, this is what I am trying to do by way of simple demonstration;
I create Table A (January) in Worksheet 1
I create Table B (January Summary) in Worksheet 2 - this contains formulas drawing information from Table A
I duplicate Table A in worksheet 1 to make Table C (February) - and overwrite the cells with new data values. Table C remains in worksheet 1
I duplicate Table B in Worksheet 2 to make Table D (February Summary). Table D remains in Worksheet 2. However, all the data values are still drawn from Table A (January). I now want them all to point to Tabel C (February) without having to manually re set all the formulas.
There doesn't appear to be a one command way of doing this. Nor can I double click the cell formulas and type in a simple change - it seems I have to start the formula set up all over again.  Any help would be appreciated - even if it is bad news! I'm quite new to Numbers - but finding my way around!
Many thanks

Answer 1

Hi John,
Rather than struggling with so many separate tables and formulas, which sounds unwieldy and error-prone, have you considered entering your data in one table and extracting monthy summary statistics and views as needed?  For example you could have something like this:
The Purchases Data table contains only data you enter. There are no formulas there.
There is only one formula in the Summary table, here copied from B2 across and down:
    =SUMIFS(Purchases Data::$D,Purchases Data::$B,$A2,Purchases Data::$C,B$1)
Granted, it's an indimidating-looking formula. But if you look up SUMIFS in the function browser you'll see how it works. It's much easier than it looks.  The first argument within the () is the column you want to sum. The other arguments are column-condition pairs, where each condition applies to the column just before it.
So the formula here in B2 is saying, add up all the numbers in column D of the Purchases Data table (the first argument) where the value in column B of the the Purchased Data table is the same as the value in A2 of the Summary table (the first column-condition pair) and the value in column C of the Purchases Data table is the same as the value in B1 of the summary table (a second column-condition pair). You can add more column-condition pairs as needed.
Using this approach you can also quickly extract monthly summary tables.  In this simple example, you set one up and get it working for the first month, then copy/paste the whole table, change its name and the month number in A1 and you're done. No need to further fuss with formulas:
Formula in B2, copied to C2:  
      =COUNTIFS(Purchases Data::$B,$A$1,Purchases Data::$C,B$1)
Formula in B3, copied to C3:  
      =SUMIFS(Purchases Data::$D,Purchases Data::$B,$A$1,Purchases Data::$C,B$1)
Then, say, you want to list all the Cafe purchases in January, you simply apply a filter to the Purchase Data table like this:
SG
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