A story book, Xiao Ming read (1/5) on the first day, 28 pages on the second day, and 52 pages left. How many pages does this storybook have? (solution with equation)
一本故事书，小明第一天看了(1/5)，第二天看了28页，还剩下52页没有看完．这本故事书有多少页？(用方程解答)
<gadget id="calculator">28 + 52</gadget>
<output>80</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">80 / (4/5)</gadget>
<output>100</output>

<result>100</result>