Xiaohong reads a book. She reads (1/3) of the whole book on the first day, and (1/4) of the whole book on the second day, and there are 30 pages left. How many pages does this book have? (solution with equation)
小红看一本书，第一天看了全书的(1/3)，第二天看了全书的(1/4)还剩下30页没看，这本书一共有多少页？(用方程解答)
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/3) - (1/4)</gadget>
<output>5/12 = around 0.416667</output>

<gadget id="calculator">30 / (5/12)</gadget>
<output>72</output>

<result>72</result>