bottle of honey weighs 1300 grams, and a bottle of kerosene of the same volume weighs 1000 grams. The two empty bottles have the same mass, and kerosene is half the weight of honey. How much does an empty bottle weigh in grams?
一瓶蜂蜜重1300克，同样容积的一瓶煤油重1000克，两个空瓶质量相等，并且煤油比蜂蜜轻一半．一个空瓶重多少克．
<gadget id="calculator">2 * 1_000</gadget>
<output>2_000</output>

<gadget id="calculator">2_000 - 1_300</gadget>
<output>700</output>

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

<gadget id="calculator">700 / 1</gadget>
<output>700</output>

<result>700</result>