Mom goes to the store to buy an apple, gives the salesperson 30 yuan, and gets back 4.80 yuan. How much did it cost to buy the apple?
妈妈去商店买苹果，交给售货员30元，找回4.80元，买苹果花了多少元？
<gadget id="calculator">30 - 4.8</gadget>
<output>25.2</output>

<result>25.2</result>