Rounded and valid figures: one more may be false
The valid digital digits of the measurements are determined by the precision of the instrument, and blind retention of decimals is misleading.
Rounded to the point that it seemed simple, the real difficulty was to keep a few. Valid figures refer to all reliable figures from the first non-zero figure, which reflects the true accuracy of the measurements. It would be absurd to use a scale that can only be precise to the grams, because the scales themselves have only two valid numbers, and the numeric numbers are purely imaginary.
Rules and common errors
- Rounded to see one after the reservation. Five to one.
- The middle is five and the back is zero, and the banker is rounded to even.
- Number of decimal places not exceeding the least accurate entry
- The valid number of multiplier results does not exceed the minimum number of valid numbers
Many computational errors stem from insensitivity to accuracy: the ratio of 1.2 m (two valid numbers) to 3.45 m is 4.140 m, which is actually about 4.1 m. This is similar to the logic of supersing the dimensional coefficients in [unit-conversion-pitfalls], which tends to accumulate with more errors. Accuracy of ratio and scaling is found in [ratio-and-scaling] (/ratio-and-scaling).
Engineering versus day-to-day trade-offs
Day-to-day calculations do not have to pursue long decimals, such as cooking recipes with 1.3 grams more honest and practical than 1.333 grams. However, the financial and scientific scene is to be kept in accordance with the norms. Quick estimates can be accompanied by [percentage heart calculation techniques] (/mental-percentage-tricks) Quantifications, followed by decisions to retain several. The statistical description is given in [median number of averages] (/mean-median-mode).