CHICKEN & RABBIT
Chicken & rabbit, solve in seconds.
Enter total heads and legs to solve by the assumption method, with random practice — a classic primary-school olympiad problem.
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Solution animation · assumption
Assume all in the cage are chickens: 8 heads
What is this?
Given the total heads and legs of chickens (2 legs) and rabbits (4 legs), solve by assuming all are chickens: rabbit = (legs − 2×heads) ÷ 2, chicken = heads − rabbit. Generate random quizzes below.
示例与注意事项Example & notes
一个例子A worked example
头 35 只、脚 94 只：假设全是鸡只有 70 只脚，差 24 只，每换一只兔多 2 只脚，所以兔 12 只、鸡 23 只。35 heads, 94 legs: all chickens would give 70 legs, a shortfall of 24, and each rabbit adds 2 — so 12 rabbits and 23 chickens.
注意事项Things to watch
- 假设法的抓手是「脚数差」除以「单只脚数差」。The assumption method is just the leg shortfall divided by the per-animal difference.
- 脚数必须是偶数，否则题目本身无解。The leg count must be even, otherwise the puzzle has no solution.
- 动画会逐只把鸡换成兔补脚，适合给孩子讲清"为什么要除"。The animation swaps chickens for rabbits one by one, which explains why the division works.
相关问答More Q&A
为什么可以先假设全是鸡？Why assume all chickens?
假设只是构造一个便于计算的起点，无论假设成什么，结论都一样。It is just a convenient starting point; the answer does not depend on which animal you assume.
能自己出题吗？Can I enter my own numbers?
可以，输入头数与脚数即可；无解时会明确提示。Yes — enter heads and legs; impossible combinations are flagged.