There were $$9$$ pieces of paper. Some of them were cut into three pieces. As a result, there are now $$15$$ pieces of paper now. How many pieces of paper were cut? ($$2005$$ Math Kangaroo Problem, Level $$3-4$$, Question \#$$17$$) 
Overseas Competition->Knowledge Point->Calculation Modules->Whole Numbers->Mixed Operations
$15-9\times1=6$  $6\div(3-1)=3$ pieces of paper were cut. 