For a bundle of rope, there are 7 meters more (2/5) left after it is used up, and there are 20 meters left. How long is this bundle of rope in meters?
一捆绳子，用去它的(2/5)还多7米，还剩20米，这捆绳子长多少米．
<gadget id="calculator">7 + 20</gadget>
<output>27</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">27 / (3/5)</gadget>
<output>45</output>

<result>45</result>