A circular steel pipe has an inner diameter of 4 cm, a wall thickness of 2 cm, and a length of 2 meters. How much does this steel pipe weigh in kilograms? (Steel weighs 7.8 kg per cubic decimeter)
一根圆形钢管，内直径4厘米，壁厚2厘米，长2米，这根钢管重多少千克？(钢每立方分米重7.8千克)
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

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

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

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

<gadget id="calculator">16 - 4</gadget>
<output>12</output>

<gadget id="calculator">100 / 1_000</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">7.8 * 3.14 * 12 * 2 * (1/10)</gadget>
<output>58.7808</output>

<result>58.7808</result>