SI units - set of 7 basic units from which all other units are derived  

• kilogram (kg) - measures mass (amount of material in an object)
• meter (m) - length
• second (sa) - time
• Kelvin (K) - temperature, where 0° is absolute zero; 273.15 more than Celsius
• mole (mol) - amount of a substance
• ampere (A) - electric current
• candela (cd) - luminosity

prefixes of metric system  

• Giga (G) - 109
• Mega (M) - 106
• Kilo (k) - 103
• Deci (d) - 10-1
• Centi (c) - 10-2
• Milli (m) - 10-3
• Micro (µa) - 10-6
• Nano (n) - 10-9
• Pico (p) - 10-12
• Femto (f) - 10-15

derived SI units - uses a combination of SI units  

• volume - measured by cubic meter or liter (equal to cubic decimeter)
• density - amount of mass per unit volume; mass/volume