When Xiao Ming reads a book, the ratio of the number of pages he has read to the number of unread pages is 2:7. If he reads another 22 pages, the ratio of the number of pages he has read to the number of unread pages is 3:5. How many pages does this book have?
小明读一本书，已读和未读的页数的比是2：7，如果再读22页，那么已读的页数和未读的页数的比是3：5．这本书有多少页？
<gadget id="calculator">3 + 5</gadget>
<output>8</output>

<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">2 + 7</gadget>
<output>9</output>

<gadget id="calculator">2 / 9</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">(3/8) - (2/9)</gadget>
<output>11/72 = around 0.152778</output>

<gadget id="calculator">22 / (11/72)</gadget>
<output>144</output>

<result>144</result>