What is the quotient of the sum of 400 and 200 divided by their difference?
400与200的和，除以它们的差，商是多少．
<gadget id="calculator">400 + 200</gadget>
<output>600</output>

<gadget id="calculator">400 - 200</gadget>
<output>200</output>

<gadget id="calculator">600 / 200</gadget>
<output>3</output>

<result>3</result>