Excel VBA - Copy a Column from Table"TBL_IMPORT" and change value during coping

Question

I use

Sheets"PrepCalc".ListObjects("TBL_PrepCalc").ListColumns.Add ... 

to copy some whole columns from a "TBL_IMPORT" table on an "Import" Sheet. Works fine.

But there are Columns that need some adjustment and calculation, like f.e. Sheet "Import" - Table "TBL_IMPORT" Column "Area" contains the text string "125000000000mm3" and needs to be placed as '12,5' (as a number) in the column "Area" at the end of the "TBL_PrepCalc" table.

Another column named "width" is also text with f.e "38mm" as value and has to read in the new column as a number value '38'.

The import table can contain 4500-10000+ rows and 18 columns. ± Half of the columns needs to be changed when copied. What is the best way to work as efficiently as possible?

At first I was thinking to walk through each row, create an universal function that take the "import_table_column" as argument1; the function "Do_the_Area_convert()" that do the math as a argument2; target column as Argument3.

Any suggestions? Being looking for this at this forum and googling around the world, but still haven' found what I'am looking for.

thank you