Sum of lines in 2 DataTables

Hello. Please help me.
File1.xlsx (10.9 KB) File2.xlsx (10.8 KB) Последовательность1.xaml (16.8 KB) I have 2 Excel tables. I need to add the values of each row of the column named 6 in one table to the values of the rows from column 6 in another table. Then perform a series of calculations and save it all to the third Excel file. I have a problem in calculating the sum of rows from different tables. I attached the process, please see what my mistake is.

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