The rice is 2.25 yuan per kilogram. Xiao Li bought 12 kilograms of rice and paid 50 yuan. How much should he get back?
大米每千克2.25元，小李买了12千克大米，付出50元，应找回多少元？
<gadget id="calculator">2.25 * 12</gadget>
<output>27</output>

<gadget id="calculator">50 - 27</gadget>
<output>23</output>

<result>23</result>