After reading a book on the first day, the ratio of the number of pages read to the number of unread pages is 1:2, and after reading 20 pages on the second day, the ratio of the number of pages read to the number of unread pages is 2:3 , May I ask from which page do you start reading the next day?
读一本书，第一天读后发现已读的页数与未读的页数比为1：2，第二天读20页后发现已读页数与未读页数比为2：3，请问第二天是从第几页开始读的呢？
<gadget id="calculator">2 + 3</gadget>
<output>5</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 + 2</gadget>
<output>3</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(2/5) - (1/3)</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">20 / (1/15)</gadget>
<output>300</output>

<gadget id="calculator">300 * (1/3)</gadget>
<output>100</output>

<gadget id="calculator">100 + 1</gadget>
<output>101</output>

<result>101</result>