There are two oil bottles, big and small, containing a total of 12 kilograms of oil. After pouring out the same amount of oil from both bottles, the remaining oil is 5 kilograms and 3 kilograms respectively. Ask how many kilograms of oil are in the big bottle.
有大小两个油瓶，一共装油12千克，两个油瓶都倒出同样多的油后，剩下的油分别是5千克、3千克．问原来大瓶有油多少千克．
<gadget id="calculator">12 - 5 - 3</gadget>
<output>4</output>

<gadget id="calculator">1 + 1</gadget>
<output>2</output>

<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">5 + 2</gadget>
<output>7</output>

<result>7</result>