How much sand is needed to add a layer of sand 5 cm thick to a road that is 5 kilometers long and 8 meters wide?
在一条长5千米，宽8米的公路上辅上一层厚5厘米的沙土，需要多少沙土？
<gadget id="calculator">5 * 1_000</gadget>
<output>5_000</output>

<gadget id="calculator">5 / 100</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">5_000 * 8 * (1/20)</gadget>
<output>2_000</output>

<result>2_000</result>