Xiao Ming spent 50 yuan to buy 4 notebooks worth 12 yuan each. Is the money enough? How much should I get back?
小明用50元钱，买了4本12元一本的笔记本，钱够吗，应找回多少元？
<gadget id="calculator">12 * 4</gadget>
<output>48</output>

<gadget id="calculator">50 - 48</gadget>
<output>2</output>

<result>2</result>