Forecast next month with the average monthly change, step by step

About this exercise

A shop owner wants a simple December forecast from the last four months. Write exactly 4 labeled lines in plain text, under 90 words: Changes, Average change, Forecast and Caveat. Use sales without the one-time item, show each change and the average with the division, round to one decimal in $ thousands, and keep the caveat to one sentence.

Common mistakes when you ask AI for this

• Keeping the wedding order. The AI uses 115 for September and gets a different average. Try: Add: "Use September as 110, without the one-time $5K."
• Skipping the steps. The AI jumps to a forecast. Try: Add: "Show the changes, the average (10 + 10 + 6) / 3, and 126 + 8.7."
• Overconfident. The AI presents the number as a firm prediction. Try: Add: "Caveat: one sentence on the holiday lift this method ignores."
• Leaving the format to chance. The AI picks its own length and layout unless told the exact shape. Try: Add: "Plain text, no bold or headings."
• 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 four labels
• Removes the one-time item
• Shows the average
• Shows the forecast
• Caps the caveat

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