COMPUTER SYSTEMS RESEARCH
Elements of Technical Writing
2005-2006
If a number is an approximation, write it out.
Writing an approximation as a decimal implies a degree of precision that is not there.
half a glass of water
a quarter of a mile down the road
one-third less energy required
You can use "hedge" words and phrases such as about, up to, almost, more or less, roughly, approximately, and on the order of to indicate an even greater degree of uncertainty
approximately one-third less energy required
up to twice the pressure