A professional poultry farmer raised 2,700 chickens and ducks last year. The number of chickens raised this year has increased by 9% compared to last year, and the number of ducks raised has decreased by 153 compared with last year. It is known that a total of 2,682 chickens and ducks were raised this year. How many chickens were raised last year?
某养禽专业户去年养鸡鸭2700只．今年养鸡只数比去年增加9%养，养鸭只数比去年减少153只，已知今年共养鸡鸭2682只，问去年养鸡多少只？
<gadget id="calculator">2_682 - 2_700</gadget>
<output>-18</output>

<gadget id="calculator">153 + (-18)</gadget>
<output>135</output>

<gadget id="calculator">9 / 100</gadget>
<output>9/100 = around 0.09</output>

<gadget id="calculator">(9/100) - 1</gadget>
<output>-91/100 = around -0.91</output>

<gadget id="calculator">1 + (-91/100)</gadget>
<output>9/100 = around 0.09</output>

<gadget id="calculator">135 / (9/100)</gadget>
<output>1_500</output>

<result>1_500</result>