Buy 2.5 kilograms of fruit candies and pay 20 yuan? Get back 4.25 yuan, how much is it per kilogram of fruit sugar?
买2.5千克水果糖，付出20元钱？找回4.25元，每千克水果糖多少元？
<gadget id="calculator">20 - 4.25</gadget>
<output>15.75</output>

<gadget id="calculator">15.75 / 2.5</gadget>
<output>6.3</output>

<result>6.3</result>