Xiaohong reads a novel and reads 30 pages on the first day. From the second day on, the number of pages I read every day was 4 pages more than the previous day, and I read 70 pages on the last day, which was just finished. Q: How many pages does this novel have?
小红读一本长篇小说，第一天读了30页．从第二天起，每天读的页数都比前一天多4页，最后一天读了70页，刚好读完．问：这本小说共有多少页？
<gadget id="calculator">30 + 70</gadget>
<output>100</output>

<gadget id="calculator">70 - 30</gadget>
<output>40</output>

<gadget id="calculator">40 / 4</gadget>
<output>10</output>

<gadget id="calculator">10 + 1</gadget>
<output>11</output>

<gadget id="calculator">11 / 2</gadget>
<output>11/2 = around 5.5</output>

<gadget id="calculator">100 * (11/2)</gadget>
<output>550</output>

<result>550</result>