A has 10 books and B has 6 books. How many books should A give B to make them both have the same number of books?
甲有10本书，乙有6本，要使两人的书一样多，甲应给乙多少本．
<gadget id="calculator">10 - 6</gadget>
<output>4</output>

<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<result>2</result>