Guangming Village has 120 color TV sets per 100 households this year, an increase of 40 sets over last year. What percentage is the increase over last year?
光明村今年每百户拥有彩电120台，比去年增加40台，比去年增长了百分之几？
<gadget id="calculator">120 - 40</gadget>
<output>80</output>

<gadget id="calculator">40 / 80</gadget>
<output>1/2 = around 0.5</output>

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