A cylindrical steel pipe has an inner diameter of 4 cm, an outer diameter of 6 cm, and a length of 2 m. Steel weighs 7.8 grams per cubic centimeter. How much does this steel pipe weigh?
一根圆柱形钢管，它的内直径4厘米，外直径6厘米，长2米．每立方厘米钢重7.8克．这根钢管有多重？
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">3.14 * 9</gadget>
<output>28.26</output>

<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">3.14 * 4</gadget>
<output>12.56</output>

<gadget id="calculator">28.26 - 12.56</gadget>
<output>15.7</output>

<gadget id="calculator">7.8 / 1_000</gadget>
<output>0.0078</output>

<gadget id="calculator">15.7 * 2 * 100 * 0.0078</gadget>
<output>24.492</output>

<result>24.492</result>