Additional question: A book with 400 pages, read the whole book (1/4) on the first day, and the remaining half on the second day, which page should you start reading on the third day?
附加题：一本书400页，第一天看了全书的(1/4)，第二天看了余下的一半，第三天应从第几页看起？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">400 * (1/4)</gadget>
<output>100</output>

<gadget id="calculator">400 - 100</gadget>
<output>300</output>

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

<gadget id="calculator">300 * (1/2)</gadget>
<output>150</output>

<gadget id="calculator">100 + 150 + 1</gadget>
<output>251</output>

<result>251</result>