You can use defined Variables to write parametric formulae which free Viewer users can change using Variable selectors displayed of the Sidebar, i.e change oil price or inflation rate assumptions within a defined range, but if the user must edit the formulae and save the results, they must upgrade to a Professional.
I want to show a table with columns with real data and other columns with 'User data'. Calculated fields are fixed, and user only change values in columns with 'User data', to compare 'user results' with real data.
The free Viewer is not really meant to be used as a calculator, any more than the Excel Viewer is meant to substitute for Excel. This is especially true if the IOK file is being created/saved with an Omniscope Edition lower than an Enterprise Server Commercial Publisher, which creates files that CAN be live-refreshed in free Viewers. If an IOK file is created/saved with a Professional or DataManager Edition, free Viewer users cannot enter data in cells, so cannot add missing/changed values to formula calculations. You can use low-cost Workgroup Editions to allow small groups to edit/save workflow files, but these are IOM files that do not open in the free Viewer, only other Workgroup Editions.