Prompt · Research & Analysis
Calculation Checker
Paste a figure and how it was worked out; get a verdict (correct, wrong or can't confirm), an independent recalculation, the first wrong step and the corrected number.
Use it when
- You are about to rely on a number someone else worked out: a price, a discount, a loan payment, a commission, a conversion, a growth rate.
- A spreadsheet total looks off and you want to know whether the logic or the arithmetic is wrong.
- You want a short verdict you can act on, not a maths lesson.
Skip it when
- The work is large-scale (thousands of rows, simulations). Run it in a spreadsheet or in code, then check the logic of one row here.
- You are studying maths and want a full worked solution or a proof. The Proof Assistant skill in this pack does that.
- The real question is whether an assumption is realistic ("will we grow 20% a month?"). That is a judgement call; this prompt checks arithmetic and logic.
Example
Input
[FIGURE]: Selling price €70 for a 40% margin[WORKING]: Unit cost €50. Price = cost × 1.40 = €70.[USE]: Wholesale price list; our target is a 40% gross margin.
Example output (illustrative, written by Meevra to show the target format; your model's wording will differ)
VERDICT: Wrong. A 40% margin on a €50 cost needs a price of €83.33, not €70.
RECALCULATION:
- Margin = (price − cost) ÷ price, so price = cost ÷ (1 − margin)
- Price = €50 ÷ (1 − 0.40) = €50 ÷ 0.60 = €83.33
- Backwards check: (€83.33 − €50) ÷ €83.33 = €33.33 ÷ €83.33 = 0.40
- Rough size: at a 40% margin, cost is 60% of the price, so the price is cost ÷ 0.6, more than cost × 1.4
WHERE IT WENT WRONG: Step 1. Multiplying cost by 1.40 adds a 40% markup on cost. Markup and margin are different measures: at €70 the margin is (€70 − €50) ÷ €70 = 28.6%.
ASSUMPTIONS: Prices exclude VAT, and €50 is the full unit cost. If packaging or shipping is not in the €50, the required price is higher.
IMPACT: €13.33 per unit below target, 11.4 margin points short. On 1,000 units that is €13,330 less gross profit than planned.What is inside
The full prompt has these sections. The ones marked “in the pack” come with the download.
- What it does in the pack
- Use it when on this page
- Skip it when on this page
- The prompt in the pack
- How to use in the pack
- How to run (Oct 2026) in the pack
- Example on this page
- Troubleshooting in the pack
Get Calculation Checker
The full prompt is a file you keep and reuse: the checklist and the answer format written out, with how to run it on each model. It comes in the Research & Analysis pack (3 prompts · 15 skills · 2 free), with a QUICKSTART, setup notes in every item and 12 months of updates.
All-Access 39 € vs 7 packs × 12 € = 84 € · less than buying 4 or more packs one by one
Stuck? Email support@meevra.com — we'll help you set it up.