30 butterflies fly out of the cage, exactly (2/3) of the original butterflies in the cage. Do you know how many butterflies there are?
笼子里飞出去30只蝴蝶，正好是笼子里原来蝴蝶的(2/3)．你知道原来有几只蝴蝶吗？
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">30 / (2/3)</gadget>
<output>45</output>

<result>45</result>