Mom goes to the fruit supermarket to buy fruit. Apples are 4.5 yuan per kilogram, and oranges are 3.6 yuan per kilogram. Mom bought 3 kilograms of two kinds of fruit and paid 50 yuan. How much should I get back?
妈妈到水果超市买水果，苹果每千克4.5元，橘子每千克3.6元，妈妈买了两种水果各3千克，付了50元钱，应找回多少钱？
<gadget id="calculator">4.5 + 3.6</gadget>
<output>8.1</output>

<gadget id="calculator">8.1 * 3</gadget>
<output>24.3</output>

<gadget id="calculator">50 - 24.3</gadget>
<output>25.7</output>

<result>25.7</result>