Uncle Li's apple orchard harvested 3,500kg of apples last year, and this year's production has increased by 20% compared to last year. How many kilograms of apples are harvested this year?
李大叔的苹果园去年收获苹果3500kg，今年比去年增产两成．今年收获苹果多少千克？
<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">3_500 * (6/5)</gadget>
<output>4_200</output>

<result>4_200</result>