(1) Analysis: When Xiao Ming was 10, his father was four times as old as Xiao Ming, so his father was 10×4=40, and his father was 40- 10=30 years older than Xiao Ming. This age difference will never change. The age of being a father is three times that of Xiao Ming, which means that his father is twice as old as Xiao Ming, so Xiao Ming was 30÷2= 15 at that time.

Solution: (10× 4-10) ÷ (3-1) =15 (year)

A: When Xiao Ming 15 years old, his father was three times as old as Xiao Ming.

(2) Analysis: Because ducks have two legs and cows have four legs. Suppose all ducks, a * * * has 20×2=40 legs, and lacks 56-40- 16 legs. Because cows are treated as ducks, they will lose 16 legs. Each cow is regarded as a duck, and it will lose 4-2=2 legs, so the cow has 65438+.

Answer: (56-20×2)÷(4-2)=8 (only)

20-8= 12 (only)

Answer: There are 8 cows, 12 ducks.

Thinking: Suppose all cows are?