The farm raises 1,500 roosters, and the number of hens is 4 times that of roosters. How many chickens are there in this farm?
养殖场养公鸡1500只，养的母鸡只数是公鸡的4倍．这个养殖场共养了多少只鸡？
<gadget id="calculator">1_500 * 4</gadget>
<output>6_000</output>

<gadget id="calculator">6_000 + 1_500</gadget>
<output>7_500</output>

<result>7_500</result>