In the flood fighting and disaster relief activity, the fifth grade students donated 312 yuan, 20% less than the sixth grade students. How much did the sixth grade students donate?
在抗洪救灾爱心活动中，五年级学生捐款312元，比六年级少捐二成，六年级学生捐款多少元？
<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">312 / (4/5)</gadget>
<output>390</output>

<result>390</result>