5/0.1-1/5=how much.
5/0.1-1/5=多少．
<gadget id="calculator">5 / 0.1</gadget>
<output>50</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">50 - (1/5)</gadget>
<output>249/5 = around 49.8</output>

<result>249/5 = around 49.8</result>