A storybook has 600 pages. Xiao Hua read it for 12 days, with an average of 45 pages per day. How many pages are left?
一本故事书600页，小花看了12天，平均每天看45页，还剩下多少页没有看？
<gadget id="calculator">45 * 12</gadget>
<output>540</output>

<gadget id="calculator">600 - 540</gadget>
<output>60</output>

<result>60</result>