It takes Xiao Fang 5 days to read a book. He reads (2/5) of it on the first day, and (2/7) of this book on the second day. How much of it is left?
小方看一本书要用5天，第一天看了它的(2/5)，第二天看了这本书的(2/7)，还剩下几分之几没看？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">(2/5) + (2/7)</gadget>
<output>24/35 = around 0.685714</output>

<gadget id="calculator">1 - (24/35)</gadget>
<output>11/35 = around 0.314286</output>

<result>11/35 = around 0.314286</result>