A fruit wholesaler buys 120 boxes of apples, each weighing 20 kilograms, and sells 1200 kilograms. How many kilograms are left?
水果批发店进120箱苹果，每箱20千克，卖出1200千克，还剩下多少千克？
<gadget id="calculator">120 * 20</gadget>
<output>2_400</output>

<gadget id="calculator">2_400 - 1_200</gadget>
<output>1_200</output>

<result>1_200</result>