Xiaohong reads a story book, she reads (2/5) on the first day and (1/5) on the second day, what percentage of the book is left unread?
小红看一本故事书，第一天看了(2/5)，第二天看了(1/5)，还剩全书的几分之几没有看？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

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

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

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