A car starts from Dalang, Dongguan, and goes to Zhangjiajie, Hunan. It travels 90 kilometers per hour and arrives at the destination in 21 hours. How many kilometers has it traveled in total?
一辆小汽车从东莞大朗出发，开往湖南张家界，每小时行90千米，21小时到达目的地，一共行了多少千米？
<gadget id="calculator">90 * 21</gadget>
<output>1_890</output>

<result>1_890</result>