Compute customer concentration with running totals and a flag

About this exercise

Build a table with the header Customer | Revenue ($M) | Share | Cumulative share | Flag for the five customers, sorted by revenue, largest first. Share is revenue divided by total company revenue, rounded to a whole percent, and cumulative adds the shares down the table. Flag is Over 15% when a customer's share is more than 15 percent, otherwise OK. Use the latest figures. Plain text, under 100 words.

Common mistakes when you ask AI for this

• Using the uncorrected figure. The AI keeps Birch at 6.0. Try: Say: "Use the latest figures, including Finance's correction."
• Dividing by the top five. The AI computes shares of the five-customer total. Try: Say: "Share is revenue divided by total company revenue of 50.0."
• Wrong cumulative. The AI forgets to add down the table. Try: Say: "Cumulative adds the shares down the table."
• Wrong flags. The AI flags several customers. Try: Say: "Over 15% only when the share is more than 15 percent."
• Wrong table. The AI adds a total row. Try: Say: "Exactly this header and five rows."
• Markdown. The AI bolds the flag. Try: Say: "Plain text."
• Trusting the AI to count words. AI is bad at counting. Ask for a total word limit and it often lands over it. Try: Cap each part instead, for example: "each line under 15 words."

What a strong prompt includes

• Gives the header
• Share formula
• Latest figures
• Flag rule
• Sort

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