SM123 Scales in Space and Time

- large and small numbers are best expressed using scientific notation
- seven base units in the SI system and every other SI unit can be expressed as a combination of these 
Metre (m), Kilogram (kg), Seconds (s), Ampere (A), Candela (Cd, luminosity), Mole (mol, amount of substance), Kelvin (K)
giga - G - 10⁹          mega - M - 10⁶           kilo - k - 10³          hecto - h - 10²          deca - da - 10¹ 
deci - d - 10^-1          centi - c - 10^-2               milli - m - 10^-3     micro - µ - 10^-6        nano - n - 10^-9 
- an answer in a calculation cannot be more precise than the least precise number used in that calculation
- use the number of significant figures from the least precise value (smallest number of significant figures)
- zeros after the decimal point but before the first non-zero number are not included in the count of significant figures 
- zeros…