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Why hidden formulas make spreadsheets so dangerous

A spreadsheet looks like a neat table of numbers, because the logic doing the work is hidden behind the cells. When a formula is copied across a row, a single shifted cell reference can quietly multiply the wrong column while displaying a confident, precise-looking total. Unlike traditional code, spreadsheets mix data, calculation, and presentation in the same grid, making tiny errors notoriously hard to spot.

4–6 min

Questions you could explore

  • Why is a calculation error harder to spot when you only see the final number in a grid?
  • How can you test a spreadsheet before relying on it for a high-stakes decision?

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