The highway from a county to the provincial capital is 160 kilometers long, and the ordinary road is 80 kilometers long. A car travels at a speed of 80 km/h on a highway and at 40 km/h on an ordinary road. How many hours can be saved by taking the expressway from the county seat to the provincial capital compared with the ordinary road?
某县城到省城的高速公路长160千米，普通公路长80千米．一辆汽车走高速的速度是80千米/小时，走普通公路的速度时40千米/小时．从县城去省城走高速路比普通路节约多少小时？
<gadget id="calculator">80 / 40</gadget>
<output>2</output>

<gadget id="calculator">160 / 80</gadget>
<output>2</output>

<gadget id="calculator">2 - 2</gadget>
<output>0</output>

<result>0</result>