Solution: suppose there are a chicken and a rabbit.

a+b = 6b = 6a

2a+4b=20

2a+4(6-a)=20

2a+24-4a=20

24-2a=20

2a=24-20

2a=4

a=2

b=6-2

b=4

There are 2 chickens and 4 rabbits.

This is a super outline. The problem of keeping chickens and rabbits in the same cage was learned in the fourth grade and improved in the fifth grade. .......