Disclosure: this article was written with the assistance of an AI writing program.
The quote check most people skip: recompute the math
Of the seven traps in the free checklist I published last week, one gets skipped more than all the others — not because it's hard, but because it feels rude to check.
Recompute the arithmetic.
Nobody checks the math on a professional-looking PDF. The layout says "trust me," the numbers look precise, and questioning them feels like accusing the vendor of something. So the unit prices, the quantities, and the totals go unverified — and that's exactly where the generous errors hide.
What to recompute (10 minutes, a calculator)
- Units × quantities = line totals. Every line. A $45/hour rate × 40 hours is $1,800, not $1,950. Typos happen — but notice they rarely favor you.
- Line totals = grand total. Add the column yourself. Subtotals, discounts, taxes — each one is a place where a number can quietly drift.
- Quantities must match everywhere. If the summary says 12 pages and the detail lists 10, one of them is the real scope and the other is the real invoice. Find out which before you sign.
- Discounts must follow a pattern. A 10% discount applied to three lines and not a fourth, with no explanation, is a question — not a detail.
An illustration (not a real quote)
Say a quote lists:
Design work — 20 hours @ $90/hour = $1,900
20 × 90 is $1,800. That $100 gap is small enough to ignore and large enough to matter across ten lines. Maybe it's a typo. Maybe it's a test of whether you're reading. Either way, you now know something about this vendor before you've spent anything — and the fix costs one email: "Can you confirm the line total on this one?"
Why this check catches what the others miss
The other traps are about words — vague lines, missing deliverables, weasel words. Words can be argued about. Arithmetic can't. A vendor can debate what "implementation services" means; they cannot debate what 20 × 90 equals. That's what makes the math check the fastest trust test in the audit: it takes ten minutes, it needs no expertise, and the answer is unambiguous.
Run it on every quote, every time — before the signature, not after the invoice.
The full checklist: the 7-trap checklist is free — 7 Vendor Quote Traps That Cost Real People Thousands.
The system: I built the fixed audit discipline into QuoteGuard ($19, 30-day guarantee) — the same 7 traps, checked the same way, every time, inside your AI assistant: https://www.getly.store/product/quoteguard-quote-analysis-verification
Disclosure: I made it. If you audit quotes rarely, the free checklist is probably all you need.
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