Minmin reads storybooks, on the first day (1/5) and on the second day (2/5), what percentage of them are left unread?
敏敏看故事书，第一天看了(1/5)，第二天看了(2/5)，还剩下几分之几没有看？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

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

<result>2/5 = around 0.4</result>