0.5 hours is much more than 20 minutes.
0.5小时比20分钟多多少．
<gadget id="calculator">30 - 20</gadget>
<output>10</output>

<gadget id="calculator">10 / 20</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>