Aunt Wang bought 5 kilograms of rice for 50 yuan, and shared it with 21.5 yuan. How much should I get back?
王大妈用50元买了5千克大米，共用去21.5元，应找回多少元？
<gadget id="calculator">50 - 21.5</gadget>
<output>28.5</output>

<result>28.5</result>