Xiaohong reads a storybook and finishes it in 12 days. The number of pages Xiao Ming reads every day is 80% of that of Xiao Hong. How many days does Xiao Ming need to finish reading this storybook?
小红读一本故事书，用12天读完．小明每天读的页数是小红的80%，小明需要几天读完这本故事书？
<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(1/12) * (4/5)</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">1 / (1/15)</gadget>
<output>15</output>

<result>15</result>