Dad bought a popular science book for Xiao Ming. Xiao Ming read an average of 20 pages a day in the first 3 days. In the next 7 days, Xiao Ming read another 168 pages. He just finished reading this book. How many pages does this book have?
爸爸为小明买了一本科普书，小明前3天平均每天读20页，后来的7天，小明又读了168页，正好将这本书读完，这本书一共有多少页？
<gadget id="calculator">20 * 3</gadget>
<output>60</output>

<gadget id="calculator">60 + 168</gadget>
<output>228</output>

<result>228</result>