In the first week of the screening of a new film a cinema sells $$2140$$ tickets.  In the second week it sells $$320$$ less tickets than the first week.  In the third week it sells $$210$$ less tickets than the second week.  How many tickets are sold over the three weeks\textgreater{}  ~\uline{~~~~~~~~~~}~ 
Overseas Competition->Knowledge Point->Word Problem Modules->Applying Addition and Subtraction->Simple Addition and Subtraction