Zhang Ming reads a 160-page book. He reads (1/5) of the whole book on the first day and (1/4) of the whole book on the second day. How many pages are he less on the first day than on the second day?
张明看一本160页的书，第一天看了全书的(1/5)，第二天看了全书的(1/4)，第一天比第二天少看多少页？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

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

<gadget id="calculator">(1/4) - (1/5)</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">160 * (1/20)</gadget>
<output>8</output>

<result>8</result>