A cuboid container is 8 decimeters long, 45 centimeters wide, and 20 centimeters deep. There was originally 10 cm of water in the container. After a stone was completely submerged in the water, the water level rose by 5 cm. Find the volume of the stone.
一个长方体容器，底面长8分米，宽45厘米，深20厘米．容器中原来有10厘米深的水，让一块石头完全浸没水中后，水面上升了5厘米．求石块的体积．
<gadget id="calculator">45 / 10</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">5 / 10</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">8 * (9/2) * (1/2)</gadget>
<output>18</output>

<result>18</result>