Obviously read a book, read (1/7) of the whole book on the first day, and (1/8) of the whole book on the second day, what percentage of the whole book is left?
明明看一本书，第一天看了全书的(1/7)，第二天看了全书的(1/8)，还剩全书的几分之几没看？
<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">1 - (1/7) - (1/8)</gadget>
<output>41/56 = around 0.732143</output>

<result>41/56 = around 0.732143</result>