Due to the improvement of equipment in a certain chemical factory, the daily output has increased from 40 tons to 60 tons. How much has the increase been?
某化工厂由于改进设备，日产量由原来的40吨增加到60吨，增加了百分之几？
<gadget id="calculator">60 - 40</gadget>
<output>20</output>

<gadget id="calculator">20 / 40</gadget>
<output>1/2 = around 0.5</output>

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