Classes A and B each have 200 textbooks. After A gives B a number of textbooks, B will have 50% more textbooks than A.
甲、乙两班各有200本课文书，甲给乙多少本后，乙的本数比甲多50%．
<gadget id="calculator">200 + 200</gadget>
<output>400</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">400 / (5/2)</gadget>
<output>160</output>

<gadget id="calculator">200 - 160</gadget>
<output>40</output>

<result>40</result>