The distance between A and B is 840 kilometers, and the car travels 56 kilometers per hour. After 15 hours, how many kilometers will there be to B?
甲乙两地相距840千米，汽车每时行56千米，15小时后，距乙地还有多少千米？
<gadget id="calculator">56 * 15</gadget>
<output>840</output>

<gadget id="calculator">840 - 840</gadget>
<output>0</output>

<result>0</result>