Take a bamboo pole of uniform thickness (about 1 meter long), make a small hole at the midpoint and tie it with a rope. The plastic bag on the left is on the scale 3, put 4 chess pieces, and the plastic bag on the right is on the scale 4, how many chess pieces can be placed to keep the balance.
一根粗细均匀的竹竿(长约1米)，在中点的位置打个小孔并拴上绳子．左边的塑料袋在刻度3上，放4个棋子，右边的塑料袋在刻度4上，放多少个棋子才能保持平衡．
<gadget id="calculator">4 / 4</gadget>
<output>1</output>

<gadget id="calculator">3 * 1</gadget>
<output>3</output>

<result>3</result>