Happy Orchard harvested 8400kg of apples this year, 20% more than last year. How many kilograms of apples did Happy Orchard harvest last year?
开心果园今年收苹果8400kg，比去年多收了二成，开心果园去年收了多少kg苹果．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 + (1/5)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">8_400 / (6/5)</gadget>
<output>7_000</output>

<result>7_000</result>