Maths - quantitative units

When writing and working with very large or very small numbers, we use standard form.

Standard form shows the size of numbers as powers of ten.

Standard from numbers are written as:

A × 10n

where: A is a number greater than 1 but less than 10 and n is the index or power.

We use standard form with:

Large numbersA population of 120,000,000 microorganisms could be written as 1.2 × 108
Small numbersA red blood cell's diameter of 7 μm or 0.000007 m could be written as 7 × 10−6 m
CalculationsWhen multiplying: add powers. When dividing: subtract powers.
Four small numbers you need to know:
  1. milli (10−3) 0.001
  2. micro (10−6) 0.000001
  3. nano (10−9) 0.000000001
  4. pico (10−12) 0.000000000001