A rectangular lawn is 100 meters wide and twice as long as it is wide. If you walk 4 times around the lawn, how many kilometers will you walk in total?
一个长方形草坪宽100米，长是宽的2倍，沿着草坪外围走4圈，一共走了多少千米．
<gadget id="calculator">100 * 2</gadget>
<output>200</output>

<gadget id="calculator">200 + 100</gadget>
<output>300</output>

<gadget id="calculator">4 / 1_000</gadget>
<output>1/250 = around 0.004</output>

<gadget id="calculator">300 * 2 * (1/250)</gadget>
<output>12/5 = around 2.4</output>

<result>12/5 = around 2.4</result>