cube container with a side length of 4 cm is filled with water. Now insert an iron rod with a length of 1 decimeter vertically (the iron rod reaches the bottom of the container). When the iron rod is taken out, the height of the water surface in the cube container is only 3 cm, how many grams does this iron rod weigh? (1 cubic centimeter of iron weighs 7.8 grams)
一个棱长为4厘米的正方体容器里盛满水，现在垂直插入一根长为1分米的铁棒(铁棒到达容器底面)，当这根铁棒取出时，正方体容器的水面高度只有3厘米，这根铁棒重多少克？(1立方厘米铁重7.8克)
<gadget id="calculator">4 - 3</gadget>
<output>1</output>

<gadget id="calculator">1 * 10</gadget>
<output>10</output>

<gadget id="calculator">4 / 10</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">7.8 / (2/5)</gadget>
<output>19.5</output>

<gadget id="calculator">4 * 4 * 1 * 19.5</gadget>
<output>312</output>

<result>312</result>