The school canteen used 96 tons of coal this year, which is 20% less than last year. How many tons of coal was used last year?
学校食堂今年用去煤96吨，今年用去的比去年节约20%，去年用煤多少吨？
<gadget id="calculator">20 / 100</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">96 / (4/5)</gadget>
<output>120</output>

<result>120</result>