A book has 200 pages. I read (1/5) of the whole book on the first day and the rest (1/4) on the second day. How many pages are left?
一本书200页，第一天看了全书的(1/5)，第二天看了余下的(1/4)，还剩下多少页没有看？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">200 * (1/5)</gadget>
<output>40</output>

<gadget id="calculator">200 - 40</gadget>
<output>160</output>

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

<gadget id="calculator">160 * (1/4)</gadget>
<output>40</output>

<gadget id="calculator">200 - 40 - 40</gadget>
<output>120</output>

<result>120</result>