[중1 수학] 동갑내기 전현무에게 과외 받은 홍진경 (일차방정식 활용,목동스타일,eng) [공부왕찐천재]

Hyun Moo is the same age as me. But I feel distant from him because he's just so academic. (The new teacher is the same age as Jin Kyung) I repeated 12th grade because of math. I really suck at math. (A self-confession that he gave up on math) Those who are other worldly cannot be understood by those limited to the mortal realm. Don't get scared! Yeah, let's not get scared. You can solve it! (He claims he can teach them the special technique he learned in Mokdong) (My Friend's Secret to Math Success) (A study group in Seoul on a sunny day) (They enjoy a nice meal before the lesson) (Then lie down like the Real Big Brain Geniuses they are) Should we lie down for just 5 mins? We have to get this out of the way. - What's this product placement for? - No, no. - It's not product placement? - It is product placement but... (The PD got caught lying) - What's this product placement for? - This is insane. It's absolutely necessary for those studying for exams. You've all tasted Summercrush. Now they've released Sleepcrush. Are you serious? - Yes. - They released Sleepcrush? Yes! Hey, check this out. Look at how much caffeine is in this thing. Children, pregnant women and those sensitive to caffeine shouldn't consume this. This would be the best for staying awake. (Overreaction) Jin Kyung, there's no need to overreact. The advertisers don't like stuff like that. I can't tell there's any caffeine in here. It tastes so good. - Can I just say exactly how I feel? - Yes. It's like frozen Bacchus. It's like frozen Bacchus. Yeah, it's really refreshing. My eyes are opening up. Please mention that this is low sugar. Hurry up and mention it. Aren't you normally meant to tell us this before we roll the cameras? This has gotten bigger, right? But it's lower in sugar. It still has that smooth taste though. So it's... win-win, I guess. It's a total win-win. How does it taste? It really does taste smooth. Try some, Jin Kyung. Silk road. Silk road? It's like I'm walking along the silk road. Have you been? - You got all your snot in there. - Where exactly is the silk road? (Buying herself time) Where does the silk road start and finish? From the Manchu fields to Arabia. So close. Is the silk road a region? - That's right. - It's a road. A road in Korea? Where is it? Where? The advertiser just cracked up. She cracked up? The road from China to the Middle East. Then I was right! You said the plains of Manchu. It's not the plains of Manchu. (This study journey is longer than the silk road) 1, 2, 3. When you talk about Jeon Hyun Moo... Do you know what the journalism exam is? I don't know. You don't? Have we started already? We just go with it. What the journalism exam is... Go, go, go! Today's teacher: Jeon Hyun Moo Today's teacher: Jeon Hyun Moo Yonsei University English Literature major Today's teacher: Jeon Hyun Moo Yonsei University English Literature major Won the Journalism Exam 3 times and retired 3 times Today's teacher: Jeon Hyun Moo Yonsei University English Literature major Won the Journalism Exam 3 times and retired 3 times Famous for being a good son Today's teacher: Jeon Hyun Moo Yonsei University English Literature major Won the Journalism Exam 3 times and retired 3 times Famous for being a good son Born in 1977 just like Hong Jin Kyung I'm not the genius type. - I'm not all that intelligent. - Really? Especially when it comes to math, which I'll be teaching you today... I repeated 12th grade because of math. I'm really bad at math. I'm the type just keeps working at it until he gets it. I keep solving questions. I keep asking questions. If the teacher asks, "Didn't you ask this last time?" I say, "Please teach me again." Since I'm not smart. So far we've had really intelligent teachers. But Hyun Moo says he was around average for math. I want to learn math from someone like him too. I feel like he could teach us from our level. The method I teach... It's the method this teacher that helped me out a lot taught me. Because I struggled to understand the concepts so much... I remember what he taught me. - So I'll teach you exactly that. - OK! (Today's lesson: How to use linear equations) I wanted to learn this today. I'm trying to teach my daughter and it's not enough to just learn equations. It's about taking a worded mathematical problem and making equations to solve them. That's madness. That's just too hard. If you get around 20 questions. The first 8 or 9 are in equation form. So they're easy to solve if you've studied. But the ones worth lots of marks in the back are virtually as long as novels. So you can't come up with the equation. Because you have no idea what it's talking about. The teacher that taught me always focused on establishing the unknown. That's right. If you know how to establish the unknown, you've completed 50% of it already. That is correct! - Are you ready? - Let's go! Let's do this! Today, I'll just tell you to solve them no matter what. - Before you teach us how? - Before that. - That's not bad, right? - I like that. There's no need to be embarrassed between us. I would never tell anyone that they're stupid. Don't get angry if we can't solve them. Why would I get angry? I was exactly the same. Don't get scared. Don't get scared just because the wording is difficult. Don't get scared. The total of 3 consecutive odd numbers is 81, what is the value of the lowest number? Okay. This is scary. I'm gonna write out all the odd numbers first. This is a very human approach. I've seen someone write out like 200 numbers this way. I mean it... Normally you wouldn't solve it like this, right? We've gathered today so we don't have to solve it like this. - Is that so? - Yes. I think I know. The unknown odd number value is x. This is important here. The 3 consecutive numbers. Since it's the next odd number, we express that as +2. So we get x+2. Then the next number will be x+4. That's the equation for the 3 consecutive odd numbers. - This is the right form, right? - I'm so surprised right now. He figured out the principle himself. Is this right? - It's right. - I'm a genius. Shouldn't it be x + (x+1)? - Since they're consecutive numbers? - No. Is this 1? This is the odd number. Therefore you have to +2 here. You can't just add 1, then you'll get an even number. You've come up with the equation. Can you solve it too? (Unknown value x) That's the answer. I used your exact equation. You came up with this. How did you come up with this? You saw the answer, right? - Tell us honestly. - I can put everything on the line to say I didn't. You came up with that without looking at the answer? The teacher was right here. Move, please. (What's the deal with Nam Chang Hee?) 1. Set the unknown figure. 2. Then write the equation. 3. Solve it. 4. Substitute with numbers to check. That's it. Should we move on to the next question? The older brother has $8 in his piggybank. The younger brother has $2. From tomorrow, the older brother adds 20 cents a day and the younger brother adds 50 cents a day. How many days will it take for their amounts to be equal? Think carefully about what you'll designate as x. Is it 2x - 5x? You're right. That's 3 then. Something's very wrong, right? No, no. Let's do this then. This is 200... 20 days! This is my equation. She's right. They're exactly the same! Yeah, I got it right up to here. You're making use of this already. You're already making use of linear equations. The first thing to do is underline the unknown value. In this case, the number of days is x. Just draw it up. There's no need to write the equation first. You have the older brother's piggybank and the younger brother's piggybank. The older brother already has $8. The younger brother has $2. So the number of days is x. The older brother gets 20 cents every day. The younger brother gets 50 cents every day. How much more will the older brother have in 2 days. 40 cents. - What about in 3 days? - 60 cents. That means this is x. The number of days is the same. This is 500x as well. When will they be the same when you add them? How many days will it be? (The number of days = x) (Amount in piggybank after x number of days) (Amount in piggybank after x number of days) (How long will it take for these sums to be equal?) (Answer: 20 days) (I can't believe I solved this) (Heavy breaths) This is like the K-Pop idol ending pose. Beastly idols... Very good. Let's use this momentum to move on to the next one. A basketball player took 12 shots in total made up of 2 point shots and 3 point shots to score 29 points. Then how many 3 pointers did he score? This one's really hard. It's hard, right? They're starting to get tougher now. The unknown figure... Is the number of 3 pointers. I don't get it. It's okay even if you don't get it. It's too hard. The examiner is exclaiming in delight at this point. "Yeah, I got you now. It was easy earlier, huh?" That's what he's saying. What's hard about this question? We can't come up with the equation. You can't work out the equation? What's the unknown figure? The 3 pointers. The number of 3 pointers is x. It's not 2 pointers for sure. What I could really relate to as I saw Dong Hyun's work... The number of shots that went in is x. So he included 2x as well. This is what messes you up. The number of 2 pointers and the number of 3 pointers are different. That's right. So you can't write them both out as x. With the piggybank question earlier, since the number of days is the same, they're both x. We can't have both of these be x. The number of 3's and 2's are different. Since we've said the number of 3's is x. Then we have 2 pointers multiplied by a number. Then we add that to the number of 3 pointers. Then we have the total number of points. That's 29. This part's easy. This is 3x... This part's the problem. This is the crazy part. What's the clue above that? It says here that the total number of shots is 12. What's the 12? There's no part of a question that's there for no reason. That's right, we can use all this. We used all the rest except this part. What's the 12? A number. Number of what? The total of 2's and 3's. It's the total number of 2's and 3's, right? Yes. If the number of 3's is x... How do we express the number of 2's with x? 12 - x. Correct! You had to minus it. 12 is the total number. It's the total number of shots including 2's and 3's. He only got x number of 3's in. Then how many 2's did he get? 12 - x. You just have to minus x from 12. So this becomes 12 - x. 2(12 - x) + 3x = 29. (The unknown figure of x) (The number of points from 3's) (The number of points from 2's) (Total score) (Number of 3's = 5) I think that was really important. That there's a reason for every part of the question. He's right. I kept looking at this 12. I knew I had to use it... We determined that x is the number of 3's. Then you might think that the 2's should be represented by y. But you can't solve it if there are 2 unknown numbers. You can! You can solve it as an open equation. Have you learned open equations or not? We have. Can you show us? Yes, I can. If 12 - x is difficult... We can make the value of 2's as y. We only want to find x, we have no interest in y. We only need to work out this. Now it becomes an open equation. We know open equations. What's the information we know? The number of points from 3's is 3x. Plus 2y = 29. With just this, we can't solve either of them. We need two for an open equation. So the question is, what is x + y? This is 12. Then what's y? 12 - x. (With the method of substitution, move one unknown figure to work out equation of other unknown figure) We simply skipped this step earlier. If you can't figure that out right away, you can do an open equation and get this. This is good! This is good. Open equations... I like this method. Don't get scared just because there are many unknown figures. Just don't get scared. Don't get scared! If you have two unknown figures, you just need two lines to solve it. Solve it! If you have three unknowns, you just need three to solve it. Solve it! If I had met a teacher like Hyun Moo during my school days, I would've gone to Yonsei University too. Those who walk in the heavenly realm can't be understood by those in the earthly realm. So true. (Thank you for a teacher from the earthly realm) Let's solve the very last question. Okay! The highlight of today. There are 3 consecutive even numbers. 4 times the largest of these is 50 more than the total of the remaining 2 numbers. What is this largest number? This one's real tough. He's angry because you keep getting them right. So he's making them tougher. I don't know where to add this 50. My math teacher always told me... Those who are bad at language are bad at math too. If you can't understand the question, you end up lost. Where is 50 bigger? The equals sign... This is insane. Is this right? Your answer... It's not finished yet, right? That's right. A lot of people repeated because they submitted their answer like that. I'm being serious. It's so close! You got most of the answer... I can never repeat! If you don't want to repeat, you need to check your answer. Okay. (Let's check Chang Hee's answer of 22) (If the largest number is 22, the others are 18 and 20) (4 times the largest number: 4 x 22 = 88) (The sum of the other two numbers: 18 + 20 = 38) (Larger than 50) (Checking the answer shows that Chang Hee is right) Amazing. He's doing really well. I've been activated. (Jin Kyung's answer is 18) It's such a shame seeing her answer. This is how you develop a grudge at Noryangjin. This is like running home coz you really need to poop then going in your pants as you unlock the door. That's not going as you unlock the door. That's like unlocking the door then going inside your door. - You even opened the door. - You got the door open... (Dong Hyun got the answer too) (Very good) I got it. Show us! Jin Kyung... You pooped your pants. Right in front of your door. The answer is 22. How did you get 24? Me? With the 3 consecutive even numbers... I wrote them as x, x+2, and then x+4. It says the largest number, right? So this one's the largest number. It said 4 times that number. So 4(x + 4)= ... It's the total of the other 2 numbers, right? So we get x + (x + 2) Then we have to add 50 here to fit the question. That is correct. So I replaced these x's with 18. This is 18. This is 20. This is 24. Why is that 24? That's 22. - I did 20 + 4. - Yes. Instead of 18 + 4... As soon as you opened the door, you pooped your pants. You had the answer. The reason why you get these errors... You needed to identify x in a better way. What is x in this question? The largest number. You should make x the largest number. Then it's 3 consecutive even numbers, right? And this one's the largest. Then how do you express the even number before this one? x - 2. This makes it easier. Then what's after that? x - 4. Then you just have to find x for the answer. Why think of getting 18 then adding 2 and 4? You can get the answer right away with this. Exactly. Then it'd be really easy. 4x = 50 + the sum of the other two. Let's add the other two first. It's all about whether you add or take away 50 from here. 4x is 50 more than these two together. Do we add or minus from here to make this equal? - Add. - That's right. Then it becomes equal. But many people end up minusing this. (This is the best equation) What the question is asking is the unknown figure, the x. There are people who solve it like this. But if you establish the x in this way, you need to be on full alert. And know that x refers to the lowest number. And that you have to add 4 later. If you just keep that in mind, it's okay to solve like this. Solving things like this in just 4 months... In the beginning I didn't know what language this was. I couldn't even read it. I have experiences too... I used to pretend I understood it when I really didn't. Because I was embarrassed. The others are nodding but I'd be like... And then struggle at home. Whether it's a foreign language or math, you get screwed if you act like you know. (Don't be scared and don't pretend that you know) I want to give this to all three of you. But the person that surprised me the most today... It was Chang Hee. I gave this to you already at 12 - x. The fact that you solved a linear equation instead of an open equation... - This is for you. - Thank you. You did real good. Next time... Since I had a blast today. Whatever the subject. Get this on camera. It's important. - He said he'd be a guest again. - The cameras are still rolling? - Oh, they're still rolling... - He mentioned next time. Goodbye, everyone! (The perfect teacher for us, Jeon Hyun Moo)

Channel: 공부왕찐천재 홍진경

Views: 2,538,111

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Id: PV0qJgOB0wY

Length: 17min 8sec (1028 seconds)

Published: Wed Jul 14 2021