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Scientists also have a shorthand for writing some large and small numbers using a prefix that represents a certain quantity. So the quantity 1 000 g, or 1 × 10³ g in scientific notation, can be written as 1 kg. The letter ‘k’ represents the factor ‘kilo’, or 10³. The quantity one‐thousandth of a gram or 0.001 g (1 × 10⁻³ g) can be written as 1 mg, where the prefix ‘m’ represents the factor ‘milli’, or 10⁻³. Table 0.3 gives some common prefixes, along with their symbols.

Note that the ‘k’ in kg is lowercase. The case of the unit can be very important, so make sure you pay attention to it!

Table 0.3 Some common prefixes and their values with quantities and symbols.

Factor	Number	Name	Symbol	Factor	Number	Name	Symbol
109	1 000 000 000	giga	G	10−9	0.000 000 001	nano	n
106	1 000 000	mega	M	10−6	0.000 001	micro	μ
103	1 000	kilo	k	10−3	0.001	milli	m
				10−2	0.01	centi	c
				10−1	0.1	deci	d