There are 1.5 liters in a bottle of beverage, how many liters are left after drinking (2/5).
一瓶饮料有1.5升，喝了(2/5)，还剩多少升．
<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">1.5 * (3/5)</gadget>
<output>0.9</output>

<result>0.9</result>