What is 90 minus 20% of it?
90减去它的20%后是多少．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">90 * (1/5)</gadget>
<output>18</output>

<gadget id="calculator">90 - 18</gadget>
<output>72</output>

<result>72</result>