The road from Shangrao to Wenzhou is about 180 kilometers long. During the May Day holiday, Xiaoming’s family traveled by car from Shangrao to Wenzhou Wildlife Park. If they took the expressway, they would travel 90 kilometers per hour; if they took the national highway, they would travel 60 kilometers per hour. How much time is saved by taking the expressway instead of taking the national road?
从上饶到温州的公路长大约是180千米．五一假期，小明一家自驾游从上饶出发到温州野生动物园游玩，如果走高速公路每小时行90千米；如果走国道每小时行60千米．走高速公路比走国道节省多少时间？
<gadget id="calculator">180 / 60</gadget>
<output>3</output>

<gadget id="calculator">180 / 90</gadget>
<output>2</output>

<gadget id="calculator">3 - 2</gadget>
<output>1</output>

<result>1</result>