Uncle Wang’s house used 45kwh of electricity last month. This month, energy-saving lamps were replaced, which can save electricity (1/5). How many kilowatt-hours does Uncle Wang's house use this month?
王叔叔家上个月用电45千瓦时，这个月更换了节能灯，可以节约用电(1/5)．王叔叔家这个月用电多少千瓦时？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">45 * (4/5)</gadget>
<output>36</output>

<result>36</result>