There is a cylindrical steel pipe with an inner diameter of 2 decimeters and an outer radius of 2.5 decimeters. The length of the steel pipe is 2 meters. What is the volume of the steel pipe in cubic decimeters?
有一根圆柱形钢管，内直径为2分米，外半径为2.5分米，钢管长2米，这个钢管的体积是多少立方分米？
<gadget id="calculator">2.5 ** 2</gadget>
<output>6.25</output>

<gadget id="calculator">2 * 10</gadget>
<output>20</output>

<gadget id="calculator">3.14 * 6.25 * 20</gadget>
<output>392.5</output>

<gadget id="calculator">2 / 2</gadget>
<output>1</output>

<gadget id="calculator">1 ** 2</gadget>
<output>1</output>

<gadget id="calculator">3.14 * 1 * 20</gadget>
<output>62.8</output>

<gadget id="calculator">392.5 - 62.8</gadget>
<output>329.7</output>

<result>329.7</result>