Ask Copilot to explain a formula, then verify it yourself

What you will learn

Use an AI assistant to explain a formula and verify its correction independently.

In this video

• 00:00 Verify a real Copilot answer
• 00:45 Read the four defects
• 01:30 Use Copilot on Windows or inside Excel
• 01:52 Enter the prompt and submit it
• 02:18 Read the actual Copilot correction
• 03:08 Calculate gross and discount independently
• 03:52 Reject the seeded incorrect claim
• 04:41 Copy Copilot code and test it in Excel
• 05:28 Find the cost defect on a canceled row
• 07:01 Fill all six hundred rows
• 07:45 Reconcile with the completed reference
• 08:10 Predict a zero-quantity result
• 08:52 Keep an absent product visible
• 09:12 Log an accepted correction
• 10:27 Your seven-minute practice

Key ideas

Treat an AI-generated formula as a proposal. Give it the sheet names, column meaning, intended rule, Excel version and one small synthetic example. Ask for an explanation of reference behavior and boundary cases. Avoid asking only for a formula that works, because that leaves the definition of works unstated.

The first broken sales formula adds the discount instead of reducing revenue. A confident explanation cannot make that rule correct. Independently compute four times 45 times 0.90 as 162, then compare the formula result. Include canceled rows, zero quantities and an absent product in your tests.

Keep an AI review log with the original prompt, suggested formula, your independent expected result, observed result and decision. Use the supplied example.com identities only. The exercises can be completed without an AI subscription by critiquing the intentionally incorrect suggestion below.

Your practice

Repair the four broken calculated columns, retain an explanation of each defect and log your evidence.

Download Lesson 1.4 - Practice Pack.zip from the Practice resources tab. Save a working copy, fill the blank formula cells, then compare with the Completed workbook in the pack.

Common mistake to avoid

A second AI answer agreeing with the first is not independent arithmetic verification.

Check your understanding

What makes your test independent from the suggested formula?

Optional AI extension

Ask an AI assistant to explain the exact formula you used and propose one boundary test. Supply only synthetic fields. Record its suggestion, an independently calculated expected result, the observed result and your accept or reject decision. No AI account is required to complete the core exercise.