It costs 80 cents per kilogram of cabbage. My mother bought 5 kilograms and paid the salesperson 5 yuan. How much money did I get back?
每千克白菜8角钱，妈妈买了5千克，付给售货员5元，找回多少钱？
<gadget id="calculator">0.8 * 5</gadget>
<output>4</output>

<gadget id="calculator">5 - 4</gadget>
<output>1</output>

<result>1</result>