A book, Xiao Ming read the whole book (2/7) on the first day, and there are 100 pages left, how many pages does this book have?
一本书，小明第一天看了全书的(2/7)，还剩100页没看，这本书一共有多少页？
<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">1 - (2/7)</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">100 / (5/7)</gadget>
<output>140</output>

<result>140</result>