Xiaojun is 5kg heavier than Xiaogang, Xiaogang is 2kg heavier than Xiaoming, how much is Xiaojun heavier than Xiaoming?
小军比小刚重5千克，小刚比小明重2千克，小军比小明重多少千克．
<gadget id="calculator">5 + 2</gadget>
<output>7</output>

<result>7</result>