The longest river in my country - the Yangtze River has a total length of 6400km, and the Yellow River is 278km shorter than 90% of the Yangtze River. How long is the Yellow River in kilometers?
我国第一长河--长江全长6400km，黄河比长江的90%短278km．黄河全长多少千米？
<gadget id="calculator">90 / 100</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">6_400 * (9/10)</gadget>
<output>5_760</output>

<gadget id="calculator">5_760 - 278</gadget>
<output>5_482</output>

<result>5_482</result>