The bookstore sold 420 storybooks on the first day and 149 on the second day. How much is the difference between the first day and the second day?
书店第一天卖出故事书420本，第二天卖出149本，第一天和第二天相差几本？
<gadget id="calculator">420 - 149</gadget>
<output>271</output>

<result>271</result>