A cubic oil barrel with a side length of 5 cm is filled with oil. If the oil weighs 4 kg per liter, how much does the oil weigh in the barrel?
一个棱长是5厘米的正方体油桶装满油，如果每升油重4千克，这桶油重多少千克？
<gadget id="calculator">5 / 1_000</gadget>
<output>1/200 = around 0.005</output>

<gadget id="calculator">5 * 5 * (1/200) * 4</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>