Hongxing Primary School used 200 kWh of electricity in December, which was 50 kWh less than that in November. How much was the saving?
红星小学12月份用电200千瓦时，比11月份节约了50千瓦时，节约了几分之几？
<gadget id="calculator">200 + 50</gadget>
<output>250</output>

<gadget id="calculator">50 / 250</gadget>
<output>1/5 = around 0.2</output>

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