Xiaohong reads a storybook, reads 30% of it on the first day, and reads 12 pages less on the second day than on the first day. At this time, she just reads half of the storybook. How many pages does the storybook have?
小红看一本故事书，第一天看了它的30%，第二天比第一天少看12页，这时正好看了这本故事书的一半，这本故事书共有多少页？
<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(1/2) - (3/10)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(3/10) - (1/5)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">12 / (1/10)</gadget>
<output>120</output>

<result>120</result>