The highway from A to B is 270 kilometers long, and the ordinary road is 300 kilometers long. A car travels at a speed of 90 km/h on a freeway and at 75 km/h on an ordinary road. How much time does it save to travel from point A to point B on the highway instead of taking the ordinary road?
从A地到B地的高速公路长270千米，普通公路长300千米．一辆汽车走高速公路的速度是90千米/小时，走普通公路的速度是75千米/小时．从A地到B地高速公路比走普通公路节省多少时间？
<gadget id="calculator">300 / 75</gadget>
<output>4</output>

<gadget id="calculator">270 / 90</gadget>
<output>3</output>

<gadget id="calculator">4 - 3</gadget>
<output>1</output>

<result>1</result>