A box of 20 candies, eat (1/2) on the first day, eat (1/5) of the first day on the second day, how many candies are left.
一盒糖果20颗，第一天吃去(1/2)，第二天吃去第一天的(1/5)，还剩下多少颗．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">20 * (1/2)</gadget>
<output>10</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">20 * (1/2) * (1/5)</gadget>
<output>2</output>

<gadget id="calculator">20 - 10 - 2</gadget>
<output>8</output>

<result>8</result>