The price of a kind of flour is 1.90 yuan per kilogram. Uncle Li bought 12.5 kilograms of flour and paid the salesperson 30 yuan. How much should the salesperson get back?
一种面粉的价格是每千克1.90元，李叔叔买了12.5千克面粉，付给售货员30元钱，售货员应找回多少元？
<gadget id="calculator">1.9 * 12.5</gadget>
<output>23.75</output>

<gadget id="calculator">30 - 23.75</gadget>
<output>6.25</output>

<result>6.25</result>