Xiao Ming reads a story book, 18 pages a day for the first 5 days, and 20 pages a day for the next 7 days, and he just finishes it. How many pages does this book have?
小明看一本故事书，前5天每天看18页，后7天每天看20页，刚好看完．这本书共有多少页？
<gadget id="calculator">18 * 5</gadget>
<output>90</output>

<gadget id="calculator">20 * 7</gadget>
<output>140</output>

<gadget id="calculator">90 + 140</gadget>
<output>230</output>

<result>230</result>