There are 320 ducks in a pond.  On the first night 1/4 of them get eaten by a fox.  On the second night 1/6 of the remaining ducks fly away, and on the third night 30 percent are stolen.  How many ducks remain after the three nights?
First night:320(1/4)=80
320-80=
<gadget id="calculator">320-80</gadget>
<output>240</output>
240.
Second night:240(1/6)=40
240-40=
<gadget id="calculator">240-40</gadget>
<output>200</output>
200.
Third night:200(.30)=60
200-60=
<gadget id="calculator">200-60</gadget>
<output>140</output>
140 ducks remain.

<result>140</result>