An apple orchard harvested 156 tons of apples last year, an increase of 20% over the previous year. How many tons of apples did this apple orchard harvest the year before last?
某苹果园去年收苹果156吨，比前年增产二成．这个苹果园前年收苹果多少吨？
<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">156 / (6/5)</gadget>
<output>130</output>

<result>130</result>