A cube tank with a side length of 1 decimeter is filled with water. Put a stone into the tank, and there is still (3/5) of water in the tank. Based on the above information, calculate the volume of the stone in cubic decimeters.
棱长1分米的正方体水缸装满水，往缸里放一块石头，缸里的水还剩(3/5)，根据以上信息，算出石头的体积应是多少立方分米．
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 * 1 * 1 * (2/5)</gadget>
<output>2/5 = around 0.4</output>

<result>2/5 = around 0.4</result>