Communitive means of, or belonging to, a community. It is difficult to see how that would be of any help whatsoever in expressing 2 7. Also, there are no such words as equivilent (the word is equivalent), nor expresion (it is expression).
Finally, limitations of the browser used by Answers.com means that we cannot see most symbols. In this case there is no visible symbol between 2 and 7 and I suggest that, in addition to using a spell-checker, you spell out the symbols as "plus", "minus", "equals" and resubmit your question
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