cylindrical steel pipe is 5m long, has a cross-sectional area of 20cm**2, and weighs 7.8g per cubic centimeter. How much does this steel pipe weigh in kg?
一根圆柱体钢管，长5m，横截面积是20cm**2，每立方厘米钢重7.8g，这根钢管重多少kg？
<gadget id="calculator">1 * 1_000</gadget>
<output>1_000</output>

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

<gadget id="calculator">20 * 5 * 100 * 0.0078</gadget>
<output>78</output>

<result>78</result>