A.0.2—Decimal and standard form

Standard form writes a number as a × 10ⁿ with 1 ≤ a < 10. It makes very small cells, concentrations and large population counts easier to compare and calculate.

0.00045 m becomes 4.5 × 10⁻⁴ m; when multiplying, multiply coefficients and add powers of ten, then check whether the result’s scale fits the biological context.

Changing notation does not change the quantity, and rounding too early can distort a later ratio.