Obviously, if you go to the park by car and walk for 40 minutes when you come back, if you take the car both ways and it takes 10 minutes, how many minutes will it take to walk both ways?
明明去公园，如果去时坐车，回来时步行共需要40分钟，如果来回都坐车，共需要10分钟，那么来回都步行需要多少分钟？
<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">40 - 5</gadget>
<output>35</output>

<gadget id="calculator">35 * 2</gadget>
<output>70</output>

<result>70</result>