It takes Li Cheng 18 minutes to walk from home to school. Cycling is 120 meters faster than walking per minute, and the time spent cycling is 6 minutes less than walking. How many meters per minute does Li Cheng walk?
李成从家到学校步行要18分钟，骑车比步行每分钟快120米，骑车所用的时间比步行少6分钟，李成步行每分钟多少米．
<gadget id="calculator">120 * 18</gadget>
<output>2_160</output>

<gadget id="calculator">120 * 6</gadget>
<output>720</output>

<gadget id="calculator">2_160 - 720</gadget>
<output>1_440</output>

<gadget id="calculator">6 - 18</gadget>
<output>-12</output>

<gadget id="calculator">18 + (-12)</gadget>
<output>6</output>

<gadget id="calculator">1_440 / 6</gadget>
<output>240</output>

<result>240</result>