The school cafeteria used 840 kilograms of coal in March, which was 180 kilograms less than that in April. The planned coal consumption in May was April (4/5), but the actual coal consumption in May exceeded the plan (1/10). How many kilograms of coal are planned to be used?
学校食堂三月份用煤840千克，比四月份少用煤180千克，五月份计划用煤是四月份的(4/5)，而五月份实际用煤超过计划(1/10)，五月份比计划多用煤多少千克？
<gadget id="calculator">840 + 180</gadget>
<output>1_020</output>

<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1_020 * (4/5) * (1/10)</gadget>
<output>408/5 = around 81.6</output>

<result>408/5 = around 81.6</result>