Lili's house used 50 degrees of electricity last month, and this month it has saved 10 degrees compared with last month. What percentage is the savings compared with last month?
丽丽家上月用电50度，本月比上月节约了10度，比上月节约百分之几？
<gadget id="calculator">10 / 50</gadget>
<output>1/5 = around 0.2</output>

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