Xiao Ming reads a story book, read it on the first day (2/13), and read it on the second day (5/13). How much of it is left unwatched?
小明看一本故事书，第一天看了它的(2/13)，第二天看了它的(5/13)．还剩几分之几没看？
<gadget id="calculator">2 / 13</gadget>
<output>2/13 = around 0.153846</output>

<gadget id="calculator">5 / 13</gadget>
<output>5/13 = around 0.384615</output>

<gadget id="calculator">1 - (2/13) - (5/13)</gadget>
<output>6/13 = around 0.461538</output>

<result>6/13 = around 0.461538</result>