The page numbers of the first and second books share 681 numbers, and the second book has 3 pages more than the first book, so how many pages are there in the first book?
上、下两册书的页码共用了681个数码，且下册比上册多3页，则上册书有多少页．
<gadget id="calculator">2 * 90</gadget>
<output>180</output>

<gadget id="calculator">681 - 9 - 180</gadget>
<output>492</output>

<gadget id="calculator">492 / 3</gadget>
<output>164</output>

<gadget id="calculator">100 - 1</gadget>
<output>99</output>

<gadget id="calculator">164 + 99</gadget>
<output>263</output>

<gadget id="calculator">263 - 3</gadget>
<output>260</output>

<gadget id="calculator">260 / 2</gadget>
<output>130</output>

<result>130</result>