A bag of potatoes is 50kg, how many kilograms are left after eating (2/5) of it?
一袋土豆50kg，吃了它的(2/5)，还剩下多少kg．
<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">50 * (3/5)</gadget>
<output>30</output>

<result>30</result>