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Cell, that got value as a result of summation, are not editable and grayed. By clicking on it, you can see which cells are contributing to the value of that cell. By hovering on it, you get a message "Automatically calculated totals cannot be modified".
In case sums are not equal for both rows and colums, an error message appears in a cell. By clicking on it, you can see which cells are contributing to the sum and therefore easily find why the sums are not the same along both rows and columns. By hovering on it, you get a message "The provided values sum up to different totals across rows and columns".
Manually entering data
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Please disable checkbox "Totals calculation" to manually enter data. Then simply enter values in cells by clicking on them.
To change the worksheets, select a value in a pick list in the upper left corner of the screen, below the toolbar. Thus, the entered values in the table are associated with the worksheet for that dimension (for example, the client).
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