During the May Day holiday, Wang Qiang's family took a short self-driving tour. Among them, the time spent on the road accounts for (1/5), the time for lunch and rest accounts for (3/10), and the rest is time for sightseeing. What percentage of the time for sightseeing?
五一长假期间，王强家进行了一次短途自驾游．其中路上用去的时间占(1/5)，吃午饭与休息时间共占(3/10)，剩下的是游览的时间，游览时间占几分之几？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 - (1/5) - (3/10)</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>