A pile of cabbage, half of which is eaten at noon, loses 4.5 kg, and there are 12 kg left in this pile of cabbage. How many kilograms does this pile of cabbage weigh?
一堆白菜，中午吃了全部的一半少4.5千克，这堆白菜还剩12千克．原来这堆白菜有多少千克？
<gadget id="calculator">12 - 4.5</gadget>
<output>7.5</output>

<gadget id="calculator">7.5 * 2</gadget>
<output>15</output>

<result>15</result>