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Short, honest explainers on the math behind everyday decisions — the calculations that quietly cost people money, and the numbers behind the health metrics everyone quotes. Every post shows its working.
The guides library teaches a specific calculation top to bottom; the blog takes a single idea the calculator surfaced and follows it to the conclusion. Why stacked discounts never add up the way the sign implies. Why an EMI that never changes actually pays two different things at once. Why one screening number describes millions of bodies and still shouldn't be read as a personal verdict. Each post is short on purpose — one idea, the formula behind it, and the numbers that prove it — and every claim can be checked with the linked calculator.
Posts are organized by what they help you decide, not by tool category: money posts deal with borrowing, discounting and salary math; health posts deal with the metrics people quote at each other. If you want the full step-by-step treatment of a calculation instead, the guides library and its glossary cover 60+ calculations with worked examples and FAQs.
Why 30% + 20% off is 44%, not 50%, and how to compute your true final price before the checkout page does it for you.
The same payment every month hides a shifting split between interest and principal. See a real 36-month table and where refinancing actually helps.
What the formula can and cannot see: muscle mass, fat distribution, age and ethnicity — and which companion metrics fill the gaps.
72 ÷ rate is the most quoted formula in finance. The exact error table shows where it holds (6–12%) and where it quietly misleads.
A 20×20 patio worked end to end: 5.4 cubic yards, 222 bags, and the unit trap that inflates orders 12×.
The 82,000/year energy saving is real. So is the 4.9-year payback, the fast-charging asterisk, and the depreciation question.