6 rice transplanters transplant 720 square meters in 1 hour, how many square meters can be transplanted in 2 hours by 3 same rice transplanters? (adapted from textbook)
6台插秧机1小时插秧720平方米，3台同样的插秧机2小时可插秧多少平方米？(改自课本)
<gadget id="calculator">720 / 6 / 1</gadget>
<output>120</output>

<gadget id="calculator">120 * 3 * 2</gadget>
<output>720</output>

<result>720</result>