The supermarket brings in three baskets of eggs. The first basket weighs 15.8 kilograms, which is 1.2 kilograms heavier than the second basket. The third basket of eggs is 2.5 kilograms lighter than the second basket. How much does the third basket weigh?
超市运进三筐鸡蛋，第一筐重15.8千克，比第二筐重1.2千克，第三筐鸡蛋比第二筐轻2.5千克，第三筐鸡蛋重多少千克？
<gadget id="calculator">15.8 - 1.2 - 2.5</gadget>
<output>12.1</output>

<result>12.1</result>