"Low-carbon life, save energy." Honghong's electricity consumption in April was 120 kWh, which was 30 kWh less than that in March. How much was the saving in April?
"低碳生活，节约能源．"红红家四月份用电120千瓦时，比三月份节约了30千瓦时，四月份节约了百分之几？
<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>