A cable, after using half of the total length and 4 meters more, there are 105 meters left, what is the total length of this cable in meters?
一根电缆，用去全长的一半还多4米之后，还剩105米，这根电缆全长多少米．
<gadget id="calculator">105 + 4</gadget>
<output>109</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">109 / (1/2)</gadget>
<output>218</output>

<result>218</result>