After Mr. Zhao bought 21 chickens at the market with 810 yuan, there was 75 yuan left. How much is an average chicken?
赵老师带了810元钱在市场买了21只鸡后，还剩下75元．平均每只鸡多少钱？
<gadget id="calculator">810 - 75</gadget>
<output>735</output>

<gadget id="calculator">735 / 21</gadget>
<output>35</output>

<result>35</result>