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=<<320-80=240>>240
Second night:240(1/6)=40
240-40=<<240-40=200>>200
Third night:200(.30)=60
200-60=<<200-60=140>>140 ducks remain
#### 140