Put a pebble into a rectangular parallelepiped glass tank with a length and width of 3dm and a water depth of 2.5dm. As a result, the water level rises by 2cm. If the pebble weighs 2.9g per cubic centimeter, how much does the pebble weigh in grams?
把一块石子放入一个长和宽都是3dm，水深2.5dm的长方体玻璃缸中，结果水面上升2cm，如果每立方厘米石子重2.9g，这块石子重多少克？
<gadget id="calculator">3 * 10</gadget>
<output>30</output>

<gadget id="calculator">30 * 30 * 2 * 2.9</gadget>
<output>5_220</output>

<result>5_220</result>