The factory planned to use 100 kilowatt-hours of electricity this month, but actually used 80 kilowatt-hours of electricity. How many percent was saved compared to the plan?
厂计划本月用电100度，实际用了80度电，实际比计划节约了百分之几？
<gadget id="calculator">100 - 80</gadget>
<output>20</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>