Notes
Page 4 of 20
How every calculator gets checked before it ships Boundaries, locales and a 375-pixel phone. The three checks every tool passes. Speed limits in the other unit, and the speedometer that flatters you A converted limit is never a round number, and your speedometer is legally allowed to be wrong in one direction. How big to print a QR code The working rule is scanning distance divided by ten. Everything else follows from how many modules the payload needs. Sizing an off-grid system: panels, battery, inverter Three components, three different questions, and only one of them is about how much energy you use. Choosing a page size for scans and screenshots A screenshot on A4 is a small picture in a large white field. Fitting the page to the image is usually the better answer. A 50% markup is a 33% margin Same profit, two denominators. Trades that quote markup and trades that quote margin are describing identical deals in different numbers. Anagrams, subsets, and which dictionary you are playing against LISTEN gives SILENT, ENLIST and TINSEL. Whether it also gives TELSON depends entirely on the word list. Mean, median or mode: which average to report Three answers to one question, and the gap between them is the most informative thing about your data. Amp-hours tell you almost nothing The same 100 Ah is 1,200 Wh at 12 V and 4,800 Wh at 48 V. Watt-hours are the number that travels. Why random picking keeps missing the same people Draw thirty names from a class of thirty and about eleven of them never come up. That is not a broken picker. What a journey actually costs Fuel is roughly half of it. The other half is tyres, servicing and depreciation, which is why mileage rates are double the pump price. What has to be on an invoice The EU sets a common list. The United States sets almost nothing. Both make the same document look wrong to the other.
Page 4 of 20