Classes A and B each have 100 extra-curricular books. After class A gives a certain number of books to class B, the number of extra-curricular books in class B is 50% more than class A.
甲、乙两班各有100本课外书，甲班给乙班多少本书后，乙班课外书的本数比甲班多50%．
<gadget id="calculator">100 * 2</gadget>
<output>200</output>

<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 + (1/2) + 1</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">200 / (5/2)</gadget>
<output>80</output>

<gadget id="calculator">100 - 80</gadget>
<output>20</output>

<result>20</result>