(1/2) of a number is 30, what is its (4/5)?
一个数的(1/2)是30，它的(4/5)是多少．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">30 / (1/2)</gadget>
<output>60</output>

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

<gadget id="calculator">60 * (4/5)</gadget>
<output>48</output>

<result>48</result>