It's time to stop treating spreadsheets like a final draft and start treating them like a working document. The user who submitted this query isn't alone, many of us have finished an analysis only to realize the real assignment was showing our work, not just the answers. That moment of panic is understandable, but the good news is that you don't need to start over. You need to show the logic, and that's a different skill than just calculating the result.
Visible formulas and pivot tables aren't extra busywork. They are the core of credible analysis. When a professor or a manager asks for them, they're asking for transparency. They want to see the path from raw data to insight, not just the destination. In Excel, you can display all formulas at once using the "Show Formulas" button under the Formulas tab, or you can print a worksheet with formulas visible. Pivot tables, meanwhile, are your best friend for summarizing data without rewriting everything. You can insert a pivot table from your existing data range, drag fields into rows and columns, and instantly generate the grouped calculations your assignment requires. The data you already entered is still there, you just need to re-present it.
The real mistake here isn't the work you already did. It's the assumption that the spreadsheet itself is a private workspace. In professional settings, the spreadsheet is the artifact. If you can't see how a number was derived, you can't trust it. That's why the pivot table exists: it forces you to declare your grouping logic and your aggregation method (sum, average, count) in a way that any observer can verify. Visible formulas do the same for cell-by-cell calculations. Together, they turn your spreadsheet from a black box into a tool that teaches others how you think.
So here is the practical path forward: keep your existing workbook. Add a new sheet, copy your raw data there, and build your pivot tables from that copy. On your original sheet, use the "Show Formulas" option to toggle your calculations into view, then adjust column widths so nothing is cut off. If your assignment requires printed output, set the print area to include those formula cells. You are not starting from scratch, you are adding a layer of documentation to work you already completed. That is a far smaller task than redoing everything, and it's the one skill that will serve you long after this lecture is over.