Dimensional Analysis - Good to know for high school
A fancy name, dimensional analysis is a very helpful (and easy, once you understand it) way to find answers to all sorts of science problems. Basically, all you do is multiply a number by another form of "one whole". You just pick that "one whole" to be a convenient conversion from units you don't want in the answer to units you do want in the answer.
Click http://go.hrw.com/resources/go_sc/hst/HSTMW311.PDF link to open resource.