A factory used 1800 kWh of electricity in April, which was 200 kWh less than that in March. How much was the saving?
某厂四月份用电1800度，比三月份节约了200度，节约了百分之几？
<gadget id="calculator">1_800 + 200</gadget>
<output>2_000</output>

<gadget id="calculator">200 / 2_000</gadget>
<output>1/10 = around 0.1</output>

<result>1/10 = around 0.1</result>