The area of a handkerchief is about 400 square centimeters, and the area of 100 such handkerchiefs is about how many square decimeters.
一块手帕的面积约400平方厘米，100块这样的手帕，面积约多少平方分米．
<gadget id="calculator">400 * 100</gadget>
<output>40_000</output>

<gadget id="calculator">40_000 / 100</gadget>
<output>400</output>

<result>400</result>