Lesson 7 of 7
When to trust the number
5 min read
AI just wrote you a formula, built a pivot, and drew a chart in seconds. It all looks right. But "looks right" and "is right" are not always the same number.
Confident isn't the same as correct
AI can make things up — and a spreadsheet is the perfect place to hide it. A formula that sums the wrong range, a pivot that quietly drops a category, a chart with a stretched axis: each looks polished and certain. The number arrives with no hesitation, whether it's right or wrong. So the skill isn't getting an answer — it's a five-second check before you build on it.
AI states a wrong number as confidently as a right one. A quick check is cheaper than a decision made on a bad figure.
Four fast checks
You don't need to redo the work — just probe it. Spot-check one cell: does one row's result match what you'd get by hand? Check the range: does the formula actually cover all the rows, not stop at row 20? Sanity-check the total: is it roughly the size you expected, or off by a factor of ten? Keep the original: work on a copy so a bad edit is never final.
The riskier the decision, the harder you check. A rough chart for yourself needs a glance; a budget going upward or a figure heading to a client deserves a line-by-line pass — and a second pair of eyes.
The shape of it
- —AI delivers wrong numbers as confidently as right ones — polish isn't proof.
- —Spot-check a cell and confirm the formula's range covers every row.
- —Sanity-check the total's size, and always keep the original as a copy.
- —Stay the human in the loop — the bigger the stakes, the harder you check.
AI hands you a total that looks perfectly reasonable. What's the single best first check?
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