Uncle Zhang raised 400 geese, and the number of geese was less than that of ducks (3/5). How many ducks does Uncle Zhang raise?
张大爷养了400只鹅，鹅的只数比鸭少(3/5)．张大爷养了多少只鸭？
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">400 / (2/5)</gadget>
<output>1_000</output>

<result>1_000</result>