In September, Xiao Ming’s house used 120 kWh of electricity, which is 30 kWh less than in August, and what percentage is the saving compared to August?
小明家九月份用电120度，比八月份节约30度，比八月份节约百分之几？
<gadget id="calculator">120 + 30</gadget>
<output>150</output>

<gadget id="calculator">30 / 150</gadget>
<output>1/5 = around 0.2</output>

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