A bottle of oil weighs 5 kilograms. After pouring out half of it, the weight of the bottle is 2.7 kilograms. How many kilograms of oil are there in the bottle?
一瓶油连瓶重5千克，倒出一半后，连瓶重2.7千克，瓶里原来有多少千克油．
<gadget id="calculator">5 - 2.7</gadget>
<output>2.3</output>

<gadget id="calculator">2.3 * 2</gadget>
<output>4.6</output>

<result>4.6</result>