A shopping mall saved 80 kWh of electricity last year compared to the previous year, which is exactly 10%. How many kWh of electricity was used last year?
某商场去年比前年节约用电80千瓦时，恰好节约了10%，去年用电多少千瓦时．
<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">80 / (1/10)</gadget>
<output>800</output>

<gadget id="calculator">800 - 80</gadget>
<output>720</output>

<result>720</result>