Xiao Ming reads a book, read half and 10 pages on the first day, read the remaining half and 10 pages on the second day, read the remaining half and 10 pages on the third day, and have 10 pages left. How many pages does the book have.
小明看一本书，第一天看了一半又10页，第二天看了剩下的一半又10页，第三天看了剩下的一半又10页，还剩下10页，这本书有多少页．
<gadget id="calculator">10 + 10</gadget>
<output>20</output>

<gadget id="calculator">20 * 2</gadget>
<output>40</output>

<gadget id="calculator">40 + 10</gadget>
<output>50</output>

<gadget id="calculator">50 * 2</gadget>
<output>100</output>

<gadget id="calculator">100 + 10</gadget>
<output>110</output>

<gadget id="calculator">110 * 2</gadget>
<output>220</output>

<result>220</result>