A rope, subtract (1/2) of this rope, then subtract the remaining (1/3) and 10 meters, and there are 20 meters left, how many meters is this rope originally?
一根绳子，减去这根绳子的(1/2)，再减去余下的(1/3)又10米，还剩下20米，这根绳子原来有多少米？
<gadget id="calculator">20 + 10</gadget>
<output>30</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

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

<gadget id="calculator">30 / (2/3) / (1/2)</gadget>
<output>90</output>

<result>90</result>