A watermelon, Xiaogang ate (1/10), mother ate (3/10), and there is still ((())/(())).
一个西瓜，小刚吃了(1/10)，妈妈吃了(3/10)，还剩下((())/(()))．
<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 - (1/10) - (3/10)</gadget>
<output>3/5 = around 0.6</output>

<result>3/5 = around 0.6</result>