A chicken farm newly bought 1000 chicks, of which the number of hens is three times that of roosters and there are 80 more. How many hens did the chicken farm buy?
养鸡场新买来1000只小鸡，其中母鸡的只数是公鸡的3倍还多80只．养鸡场新买来多少只母鸡？
<gadget id="calculator">1_000 - 80</gadget>
<output>920</output>

<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<gadget id="calculator">920 / 4</gadget>
<output>230</output>

<gadget id="calculator">230 * 3</gadget>
<output>690</output>

<gadget id="calculator">690 + 80</gadget>
<output>770</output>

<result>770</result>