Xiaohua reads a novel and originally planned to finish it in 20 days. I actually read 20 pages more than planned every day, and actually finished it in only 15 days. How many pages does this novel have?
小华看一本小说，原计划20天完成．实际每天比计划多看20页，实际只用15天看完，这本小说有多少页？
<gadget id="calculator">15 * 20</gadget>
<output>300</output>

<gadget id="calculator">20 - 15</gadget>
<output>5</output>

<gadget id="calculator">300 / 5</gadget>
<output>60</output>

<gadget id="calculator">60 * 20</gadget>
<output>1_200</output>

<result>1_200</result>