A bottle of ink is 60ml, used up (2/5), how many milliliters are left.
一瓶墨水60毫升，用去(2/5)，还剩多少毫升．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">60 * (3/5)</gadget>
<output>36</output>

<result>36</result>