(2/3) of a number is 30, what is 80% of this number?
一个数的(2/3)是30，这个数的80%是多少．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

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

<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">45 * (4/5)</gadget>
<output>36</output>

<result>36</result>