The Yangtze River is the largest river in my country and the third largest in the world, with a total length of 6,300 kilometers. The Yellow River is second only to the Yangtze River and is the second longest river in my country. The lengths of its upstream, middle and downstream are 3470 km, 1210 km and 790 km respectively. How many kilometers is the Yangtze River longer than the Yellow River?
长江是我国第一大河，在世界上位列第三，干流全长6300千米．黄河仅次于长江，是我国第二大河，它上游、中游、下游的长度分别是3470千米、1210千米、790千米．长江比黄河长多少千米？
<gadget id="calculator">3_470 + 1_210 + 790</gadget>
<output>5_470</output>

<gadget id="calculator">6_300 - 5_470</gadget>
<output>830</output>

<result>830</result>