3.25 yuan per kilogram of apples. Dad bought 14 kilograms of apples and paid 50 yuan. How much should he get back?
每千克苹果3.25元，爸爸买了14千克苹果，付出了50元，应找回多少钱？
<gadget id="calculator">3.25 * 14</gadget>
<output>45.5</output>

<gadget id="calculator">50 - 45.5</gadget>
<output>4.5</output>

<result>4.5</result>