There are 60 animals in a yard. Some are chickens, some are dogs. Together, they have 194 legs. How many chickens and how many dogs are there?194 legs
🐔 = 2 legs 🐕 = 4 legs
Q: How many chickens? ___
How many dogs? ___
🎙️口播（慢节奏）：
(写：题干区左上角) → "60 animals"，"194 legs"
(画：🐔 + 🐕 简笔画，标注腿数)
"You walk... into a farm.
Chickens clucking... dogs barking...
And someone gives you this:" Hypothetical Reasoning – Strategy #01
Strategy Type: Assumption-Based Modeling
Used in: Animal-leg problems, Ticket pricing, SAT Mixture Problems
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🎬 Segment 1: HOOK 引入 + 预设认知
📝【写板提示】：
• 左上角写：60 animals
• 下方写：194 legs
• 右侧写：🐔 = 2 legs 🐕 = 4 legs
• 留白：Q: How many chickens? ___ How many dogs? ___
🔴 PROBLEM:
60 animals
(指题干)
"60 animals... but 194 legs."
"No blood. No injuries...
Just a... mathematical mystery."
"Let’s figure it out. But let’s not... rush."
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🐔 Segment 2：荒唐假设（All Chickens）
Assume: All are chickens
→ 60 × 2 = 120 legs
→ Reality: 194
→ Gap = 74
🎙️口播（带停顿）：
"Let’s assume… every animal... is a chicken.
Even the one... that clearly barks."
"60 × 2 = 120 legs...
But reality gives us... 194."
"We’re short by... 74 legs.
That’s… a lot of limbs."
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🐕 Segment 3：Reasoning Through the Gap
🐔 → 🐕 = +2 legs
Gap = 74
Each dog adds +2 legs
74 ÷ 2 = 37 dogs
60 - 37 = 23 chickens ✅
🎙️口播：
"So... where did those extra 74 legs come from?"
"Every time we replace... a chicken with a dog...
We gain 2 extra legs."
"So...
How many dogs... does it take... to gain 74 legs?"
"74 ÷ 2 = 37 dogs.
That leaves us with 23 chickens."
"Total? 37 + 23 = 60.
We’re back to balance."
🎭 幽默：
"That’s a lot of barking.
Or maybe... half-leg dogs? Not on this farm."
🧠 金句：
"Total difference ÷ per-unit gain = number of substitutions."
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✅ Segment 4：验证闭环
Dogs: 37 × 4 = 148
Chickens: 23 × 2 = 46
Total: 194 ✅
🎙️口播：
"Let’s verify...
Dogs: 37 × 4 = 148...
Chickens: 23 × 2 = 46...
Total: 194."
"Boom. Verified.
From a ridiculous guess."
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🔁 Segment 5：反向路径（假设全是狗）
🎙️口播：
"Alright... so assuming they’re all chickens gave us the right answer."
"But what if... we go in the other direction?"
"Let’s assume... every animal is a dog.
Just a pack of 60 dogs... running around."
📐 推导：
60 × 4 = 240 legs (if all dogs)
But reality only gave us 194 legs.
Overshoot = 46 legs
🎙️口播：
"Now we’re 46 legs over... too many!
That’s some chunky math."
"What saves legs? Chickens. They only have 2."
"46 ÷ 2 = 23 chickens.
So... 60 - 23 = 37 dogs. ✅"
🎭 幽默：
"Good thing it wasn’t 60 dogs.
That’d be a noisy farm... and one with a serious dog food bill."
🎯 教学句：
"Two wrong assumptions. One same answer.
That’s not a mistake. That’s a method."
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📎 Segment 5.5 — The Power of Assumption（代数法 + 彩蛋延伸）
🎙️口播：
"Alright... we’ve solved the problem with chickens. Then with dogs."
"Let’s try a third way — using algebra."
🧮 方程解法：
Let x = number of dogs
Then chickens = 60 - x
Equation: 4x + 2(60 - x) = 194
→ 4x + 120 - 2x = 194
→ 2x = 74
→ x = 37 dogs ✅
🎙️口播：
"Same answer. Different route.
That’s the power of algebra."
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🎙️口播（彩蛋挑战节奏）：
"But just before we wrap up — I’ve got a challenge for you."
"There are two more ways to solve this.
But they’re weird... and sneaky."
"What if you assume... every leg is a dog leg?
Or... every leg is a chicken leg?"
"I won’t solve them for you.
That’s your bonus puzzle today."
🧩 彩蛋提示（板书留空）：
• If all 194 legs came from dogs, how many heads are missing?
• If all 194 legs came from chickens, how many heads did you overcount?
🎯 引导结束：
"If you can explain either of those...
you’ve officially unlocked Hypothetical Thinking Level 2."
"Leave your logic below.
I’ll be watching."
🧠 金句（逐句沉思）：
"Assumptions... aren’t supposed to be correct.
They’re supposed to be... correctable."
"One problem. Five paths. One truth."
"Guess wrong. Think right. Land true."
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📦 Segment 7: Strategy Migration
HYPOTHETICAL REASONING
├─ Mixtures: “Assume all water?”
├─ Averages: “Assume all perfect scores?”
└─ Work: “Assume one person does the job?”
🎙️口播：
"This strategy doesn’t end here.
You’ll see it again… in mixtures, averages, and work problems."
"Because in all of them…
we make a bold assumption... then adjust."
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☁️ Segment 8：哲学升华
🔥 Guessing = Flashlight
→ ☁️ Light into Maze (简笔画)
🎙️口播：
"We guess not to skip.
We guess... to understand."
"A good guess doesn’t jump to the answer…
It lights up where the structure breaks."
"Guessing isn’t a shortcut —
It’s a flashlight."
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🔮 Segment 9：结尾预告
NEXT: Ticket Trouble — Hypothetical Reasoning in Real Life 🎟️
🎙️口播：
"Next time… we leave the farm. And head to the ticket booth."
"50 tickets. $312 collected.
Adults pay 8. Kids pay 4."
"How many of each ticket did they sell?"
"We’ll use the same strategy — make a bad assumption, then fix it."
"That’s Hypothetical Reasoning, Part 2 — in the real world.
Strategy #02. Stay tuned."
视频信息
答案文本
视频字幕
You walk into a farm. Chickens clucking, dogs barking, and someone gives you this problem. There are 60 animals in a yard. Some are chickens, some are dogs. Together, they have 194 legs. How many chickens and how many dogs are there? Let's figure it out, but let's not rush.
Let's assume every animal is a chicken. Even the ones that clearly bark. Sixty chickens times two legs each gives us one hundred twenty legs. But reality gives us one hundred ninety-four. We're short by seventy-four legs. That's a lot of limbs.
So, where did those extra 74 legs come from? Every time we replace a chicken with a dog, we gain 2 extra legs. So, how many dogs does it take to gain 74 legs? 74 divided by 2 equals 37 dogs. That leaves us with 23 chickens. Total? 37 plus 23 equals 60. We're back to balance.
Let's verify our solution. Dogs: 37 times 4 equals 148 legs. Chickens: 23 times 2 equals 46 legs. Total: 148 plus 46 equals 194 legs. Boom! Verified. Our solution is correct.
Alright, let's try a different approach. What if we assume every animal is a dog? Just a pack of 60 dogs running around. That would give us 60 times 4, which is 240 legs. But reality only gave us 194 legs. We're 46 legs over... too many! What saves legs? Chickens! They only have 2. 46 divided by 2 equals 23 chickens. So 60 minus 23 equals 37 dogs. Two different approaches, same answer. That's not a mistake. That's a method.
Let's assume every animal is a chicken. Even the ones that clearly bark. Sixty chickens times two legs each gives us one hundred twenty legs. But reality gives us one hundred ninety-four. We're short by seventy-four legs. That's a lot of limbs.
So, where did those extra 74 legs come from? Every time we replace a chicken with a dog, we gain 2 extra legs. So, how many dogs does it take to gain 74 legs? 74 divided by 2 equals 37 dogs. That leaves us with 23 chickens. Total? 37 plus 23 equals 60. We're back to balance.
Let's verify our solution. Dogs: 37 times 4 equals 148 legs. Chickens: 23 times 2 equals 46 legs. Total: 148 plus 46 equals 194 legs. Boom! Verified. Our solution is correct.
Alright, let's try a different approach. What if we assume every animal is a dog? Just a pack of 60 dogs running around. That would give us 60 times 4, which is 240 legs. But reality only gave us 194 legs. We're 46 legs over... too many! What saves legs? Chickens! They only have 2. 46 divided by 2 equals 23 chickens. So 60 minus 23 equals 37 dogs. Two different approaches, same answer. That's not a mistake. That's a method.