For a rope, (1/2) more than 1 meter was used on the first day. The remaining (1/2) is used for 1 meter more the next day. At this time, there are 3 meters left. How many meters was the original length?
一根绳子，第一天用去(1/2)多1米．第二天用去剩下的(1/2)多1米，这时还剩3米，原长多少米？
<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 - (1/2)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">4 / (1/2)</gadget>
<output>8</output>

<gadget id="calculator">8 + 1</gadget>
<output>9</output>

<gadget id="calculator">9 / (1/2)</gadget>
<output>18</output>

<result>18</result>