There are 3690 chickens and ducks in a farm, and the number of chickens is 1/7 more than that of ducks. How many ducks are raised in this farm?
一个饲养场养鸡、鸭共3690只，养的鸡比鸭多(1/7)，这个饲养场养鸭多少只？
<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">1 + (1/7) + 1</gadget>
<output>15/7 = around 2.142857</output>

<gadget id="calculator">3_690 / (15/7)</gadget>
<output>1_722</output>

<result>1_722</result>