Units



Units are different ways of measuring things, this is an important issue as it has lead

	to many misunderstandings in the past.


e.g. 1 mile is about 15 minutes walk, 1 kilometer is about 12 minutes walk.



10 miles is therefore not the same distance as 10 kilometers.


when referring to a numerical quantity, it's important to specify the units

	that the value is in.




distance		1 mile = 1.6 kilometers


weight			1 kilogram = 2.2 pounds


volume			1 US gallon = 3.78 liters


other quantities




major systems of units



metric system, also known as the SI system

british system of units

US system of units
