A certain village produced 5.8 tons of sorghum per hectare last year, which is 20% less than last year. How many tons of sorghum per hectare this year?
某村去年每公顷产高粱5.8吨，今年比去年减少二成，今年每公顷产高粱多少吨？
<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">5.8 * (4/5)</gadget>
<output>4.64</output>

<result>4.64</result>