A rectangular paddy field is 360 meters long and 240 meters wide. If an automatic sprinkler with a range of 6 meters is used for irrigation, how many such devices are needed?
一块长方形稻田长360米，宽240米，如果用射程为6米的自动喷灌装置进行喷灌，大约需要多少个这种装置？
<gadget id="calculator">6 * 2</gadget>
<output>12</output>

<gadget id="calculator">360 / 12</gadget>
<output>30</output>

<gadget id="calculator">240 / 12</gadget>
<output>20</output>

<gadget id="calculator">30 * 20</gadget>
<output>600</output>

<result>600</result>