The probability that each child gets at least one chocolate is? 
5 different chocolates are to be distributed among 4 children.The
  probability that each child gets at least one chocolate is ?

Total number of ways is $4^5$.Got that.After that what to do?

We can say that 5/4=1
1+1(the given number in the question-at least one-)=2
so we say that there would be a child who will get two chocolate which means others have one chocolate.
