Suppose there are five cages a, b, c, d and e.
So now there are 9 rabbits in each cage, keeping C unchanged. According to the conditions, 4 rabbits in A give E, and 2 rabbits in B give D..
At this time, the number of rabbits in the five cages is 5, 7, 9, 1 1, 13.
Maybe you have found a rule to do this kind of problem. If you carefully observe the relationship between conditions and problems, you can do it quickly. I hope I can help you. ...