There are 687 numbers in the page numbers of the first and second books, and the first book has 5 more pages than the second book, so how many pages are there in the first book?
上、下两册书的页码共有687个数字，且上册比下册多5页，则上册书有多少页．
<gadget id="calculator">3 * 5</gadget>
<output>15</output>

<gadget id="calculator">687 + 15</gadget>
<output>702</output>

<gadget id="calculator">702 / 2</gadget>
<output>351</output>

<gadget id="calculator">2 * 90</gadget>
<output>180</output>

<gadget id="calculator">351 - 9 - 180</gadget>
<output>162</output>

<gadget id="calculator">162 / 3</gadget>
<output>54</output>

<gadget id="calculator">54 + 99</gadget>
<output>153</output>

<result>153</result>