Mom went to the supermarket and bought 3 kilograms of oranges, paid the salesperson 12 yuan, and got back 2.4 yuan. How much is an orange per kilogram?
妈妈到超市买了3千克橙子，付给营业员12元，找回2.4元．橙子每千克多少钱？
<gadget id="calculator">12 - 2.4</gadget>
<output>9.6</output>

<gadget id="calculator">9.6 / 3</gadget>
<output>3.2</output>

<result>3.2</result>