Getting rid of page numbers from a latex document is a tricky thing to do :) sometimes you do not want page numbers in your document but the document class or style file you are using puts page numbers...
many websites/manuals/blogs suggest the use of \thispagestyle{empty} after \maketitle tag to overwrite the style file and remove the page numbers. But some style files will still print the page numbers on all pages except the first one... if this is the case then add \pagestyle{empty} tag and the page numbers from all the pages will be removed :)... the code will look like
\maketitle
\thispagestyle{empty}
\pagestyle{empty}
this trick worked in my case where i was using ieeetr.cls as document class... i hope it works for other cases as well...
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The following things copied from comments section may also help (I thank the people who commented):
Instead I use
\renewcommand\thepage{}
to get rid of page numbers.