A cylindrical steel pipe is 20 cm long, its outer diameter is half the length, and its wall thickness is 1 cm. It is known that the steel weighs 7.8 grams per cubic centimeter. How many grams does this steel pipe weigh?
一根圆柱形钢管，长20厘米，外直径是长的一半，管壁厚1厘米，已知每立方厘米的钢重7.8克，这根钢管重多少克？
<gadget id="calculator">20 / 2</gadget>
<output>10</output>

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

<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

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

<gadget id="calculator">10 - 2</gadget>
<output>8</output>

<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">4 ** 2</gadget>
<output>16</output>

<gadget id="calculator">25 - 16</gadget>
<output>9</output>

<gadget id="calculator">3.14 * 9 * 20 * 7.8</gadget>
<output>4_408.56</output>

<result>4_408.56</result>