Question

I am studying grammer as a beginner, can sombody tell me what is wrong with number usage ; In the sixties there were sit-ins at 100's of colleges

Answer 1

well, if you are going to write "sixties" out in words rather than numbers, you have to have the same rule for "100's" - i.e. it should be hundreds, rather than "100's"

Answer 2

See OWL at Purdue for number usage: http://owl.english.purdue.edu/owl/resource/593/01/
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