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Luis has 7 apples and 2 bananas. He gives 2 apples to Yuri who, in return gives bananas to Luis. Then Luis has as many apples as bananas. How many bananas did Yuri give to Luis? 
Overseas Competition->Knowledge Point->Word Problem Modules->Applying Addition and Subtraction
$$7-2=5$$  $$5-2=3.$$ 