Xiao Ming reads 20 pages of a storybook every day for 12 days, and there are 45 pages left. How many pages are there in this storybook?
小明每天看一本故事书的20页，看了12天，还剩45页．这本故事书一共多少页？
<gadget id="calculator">20 * 12</gadget>
<output>240</output>

<gadget id="calculator">240 + 45</gadget>
<output>285</output>

<result>285</result>