Use small sticks of the same length to make a square, one is □, two are □□, three are □□□...how many sticks are needed to place 80 sticks.
用一样长的小棒摆正方形，摆1个是□，摆两个是□□，摆3个是□□□…摆80个需要小棒多少根．
<gadget id="calculator">80 * 4</gadget>
<output>320</output>

<result>320</result>