A bag of salt is 40 kg, used up (3/5), how much is left.
一袋食盐40千克，用去了(3/5)，还剩多少．
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">40 * (2/5)</gadget>
<output>16</output>

<result>16</result>