river crossing - A man, a chicken, and a fox?

A man lives in a small house with a farm as his back garden and has a river beside his house. On the other side of the river is a shop. One day, he visited the shop, he bought a chicken and a fox for his farm and bought a bag of corn to feed the chicken. The man can only take one thing and himself across in the boat. Without killing any animals, or letting one animal eat another animal or item, how will the man get across?

I heard this once but could never find a solution.

Answer

He can do it in seven steps:

1. Cross the river with the chicken.


2. Return across the river with nothing, leaving the chicken behind.


3. Cross the river with the fox.


4. Return across the river with the chicken, leaving the fox behind.


5. Leave the chicken on the shop side, and cross the river with the corn.


6. Return across the river with nothing, leaving the corn behind.


7. Cross the river with the chicken again.

At no time are the fox and chicken, or chicken and corn, left alone together.