Running along a 400-meter circular runway is exactly 1 kilometer.
沿400米的环形跑道跑多少正好是1千米．
<gadget id="calculator">1_000 / 400</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">1 * (5/2)</gadget>
<output>5/2 = around 2.5</output>

<result>5/2 = around 2.5</result>