Help: Converting Pluses and Times to Sum and Product Functions ???
 

I have converted Lotus 1-2-3 spreadsheets that are just shy of functioning
properly in the Excel environment. Lotus apparently treats text in cells as 0
or 1 values so that when they are added or multiplied (with operands) it has
no net effect on the value that results. Excel returns an error message when
using operands to sum/multiply values with text. I did discover that Excel
does what I need it to do when using the =SUM() and =Product() functions. I
updated all the formulas by hand in one sheet and then found that there are
69 more sheets and the formulas are irregular.

Does anyone have any idea how to write a VBA macro that will parse the
spreadsheet and convert all the formulas to use SUM and/or PRODUCT instead of
" + " and " * "?

Example
Convert: " =ROUND ( (+CO34 +DA34 -AA33) * DD34,0) "

To: " =ROUND (PRODUCT (SUM (CO34,DA34,-AA33) ,DD34) ,0) "
or
To: " =ROUND (PRODUCT (SUM (CO34) + SUM (CO34) - SUM (AA33) ,1) * PRODUCT
(DD34,1) ,0) "

Both methods seem to give me the same result. The second way is easier for me
to approach, but I haven't been able to nail it down.

Thank you!