Hi, this is Presh Talwalkar. In this video I’m going to teach you how you can calculate cube roots (∛) in your head. Why would you ever want to do this? The Education Secretary Nicky Morgan was recently on TV and put on the hot seat. She was asked by a ten-year-old the question, “What Is the cube root of 125?” She refused to answer any math questions on TV and I understand that. But if she knew the trick in this video, she could have answered it very quickly and done many more math problems. So to do the trick, you first have to memorize the cubes of each number from 1 to 10. The cube of a number is the number multiplied by itself three times. So the cube of 1 is still 1. The cube of 2 is 8. The cube of 3 is 27. And I’m going to keep writing the cubes of each number. So you may know some of these. Otherwise, to do this trick you’ll have to memorize these ten numbers. Now once we’ve written down these cubes, I want you to focus on the very last digit of the number of the cube. So what’s important is that each of these 10 numbers end in a different last digit. And that’ll be very important to doing this trick. So this will be another thing you have to memorize. When you memorize these 10 digits, you should also remember the last digit. So an easy way to remember this is that for the numbers 1, 4, 5, 6, 9, and 0, the last digit is the same as the numbers. And for the numbers 2 and 8, and 3 and 7, the last digit flips. So the last digit for 2 is 8, and the last digit for 3 is 7 and vice versa. So let’s do the trick. What’s the cube root of 39,304? The first thing I want you to do is look at the last digit. The last digit of 39,304 is 4, which we’re going to put in a box. So we look up 4 in the last digit, and that corresponds to the number 4. So we write down the number 4. The next step is we ignore the last three digits of our number. So in 39,304, we’re going to just ignore the 304. And now we want to find the closest cube without going over. So 39 is between 27 and 64, so it’s actually closest to 27 without going over, which means it’s closest to the cube of 3. And that gives us the other part of our answer, which is 3. So here we have it, we put the numbers together and 34 Is the cube root of 39,304. So why would this ever be useful? So here’s a trick you can do. Ask someone to pick a number from 1 to 100, and just think about it secretly, don’t have them tell you the number. Have them cube the number on a calculator. And once they cube the number, they tell you the cube and you instantly can tell them the cube root by using this table and using the trick. So let’s imagine they tell you the number is 636,056. So we look at the last digit, which is 6, and when the last digit is 6, that corresponds to the number 6. And then we look at the, we ignore the last three digits and we look at 636. That’s between the cubes of 8 and 9, so we put 8. And therefore, the cube root is 86. So once you get used, once you’ve memorized this table, you’ll actually be able to do this very quickly. Let’s do another example. 185,193 We look at the last digit of 3. That corresponds to the number 7 because 3 and 7 flip. Then we ignore the last three digits and we look at 185. And that’s closest to the cube of 5 without going over. So that gives us the answer of 57. So it’s a pretty neat trick. And if you want to know how this works, you can click through. I’ve made a short video which gives a math proof. If you like this video, please subscribe to my channel. You can support me on Patreon to get exclusive rewards. Catch me on my blog MindYourDecisions, on Twitter @preshtalwalkar. And you can get my books listed on my website.

But how to know wether a number is perfect cube or not.

This is very amazing!

School 😖

Thanks

I have tried with the number: cube root of 1157.625= 10.5

Can i download your book for free because I am poor.l hope you will give me to download for free.Can you tell me please.

What about the 1000

Ex. 1,838,283

So the answer is 07?

I can teach you a lot of really useful math tricks I learned myself

I think your last example was wrong because 185 is closest to 6=216-185= 31 & 5=125+60=185

I hope you understand

Romanian priminister is analphabet

Sir 185 is very closer to 216 but you dont do this why

It is not applicable to 1000

Okay but for the last one 185 is closer 216 then 125 so wouldn't it be 6? 185 is 60 away from 125 but only 31 away from 216

But in last ques it was closure 96 u have said 86 because 636-512,or 729-636 of couse it is wrong trick

You are genius bro

Well you see i need a better gpa then my brother so i sill thouroughly go through all your videos and practicd

Does it really work every time?

The closet to 185 is 216 , it’s not 125 so that means the number was supposed to be 6 and the result will become 67 it’s wrong man

I cant understand his trick… Anyone can tell me clear about this trick??

Someone find for number "300763"

Correct answer is '67' but according to this logic answer is '77'

That doesn't work….trs this with 88*88*88(and this is literaly the second number i tried this with..(99 was the first one)

For what joy? What's the use?

34^3 = 39 … yes of course

This is the coolest trick I've ever learned that I'll probably never use.

I would've have told the kid to SMD

Byey calculator. I am the calculator

I still don't get it

My brain is burning

How to identify a number which is not a cube of some degit. Like 59304. According to this process the answer will be 34 which will be wrong

You have to memorize these 10 cube roots

Me: close the video and say My life will never be easy

WWOOOOOOOOOOOOOOOOOOOOOOOOOOOHHHHHHHHHHHHHHHH!!!!!!!!!!!!!!!!!!!!!!!

This trick is originated from india…go find some thing else

Doesnot work for cube of 93

How u make your videos

You said closest cube without going over .What’s the thing you are trying to do ? In case of last one 185193 – I understand you take 7 first then why you take 5 why didn’t you take 4 ?need clarification

Dude delete the video its not working for 24896, it got nerfed by the Math Gods!

I actually multiplied the number by itself and then multipled it again. For example 6. 6×6=36, 36×6= 216. Just how I do it cuz it worked well on my sats

How about not perfect cubes

Boring

How to use cube root in our daily life?

What is the purpose of cube root in our daily life?

Are you from Odisha??

It doesn't work for the cube root of 117649 which is 49 but according to this method it come up with ans 59🤨?

So,can u please tell me reason behind this?

What about cube of 3 digit numbers ?

What if we have 7 digits number ? It also works in same way for 7 digits number ?

Heyyy girll can you calculate cube roots cuz i sure can

How does it work for 48?

The cube is 110,592 from last digit I get 8 den ignoring the last 3 digits the closest cube to 110 is 125 which is cube of 5..so the answer comes to be 58.

Semma trick 🤓

Are the Cube roots of 129534, 127314, 131464 same? By using your method.

Thank you..

I just came here to dislike and leave.

Neat

Can you solve this this solution one by one. Because I don't understand about your explaining

Ded

Will it work for 24389. ?

Tried this the other day. Couldn’t get it to work. I think god patched it.

wow neat, I will probably never use it though.

Excellent math trick! Thanks!

only works for perfect cubes, disappointment as expected

Good gimmick…shitty instructor.!

Oh this is so cool, helps a lot

Would've been nice to have this taught at school

Why is this in my recommenced

THANK YOUUU

Ok enough for now. I've seen enough recommendations today.

Very nice explanation!

How to calculate cube root of fraction

“Memorize the cubes of each number from 1 to 10”

nevermind

Isn't 636(for finding the cube root of 636056) nearer to 729 than 512. So this method is flawed.

Any trickfor square roots

Sorry but I don't have math as my subjects anymore and I couldn't be happier.

Nice!

4:00 No. 6 is the closest to 216

But how would you know if it's not a perfect cube?

Is this Vedic maths ? Method seems very similar to the mental system of it .

Damm, how did she not know the cube root of 125 like that's easy

I Like

Cool but useless.

Who else looked it up after he done it to check🤣

At the end he says its closer to 5, but its actually closer to 6……

Ermm how will this be of any help to me 😂 i still watched the whole vid

Too much work fr

Got this recommended

God be with us 8 I love you 8 il get you a spoon

34 one 3 on 4 on

I dont think this works.

Of course this is in my recommendations 1 week before I go to high school

Tf was this doing in my recommendation???….Why should this exist???

You think you need education to be the secretary of education in America? You just need money and connections

2019 August anyone?

636 is 31 units further from 512 than 729. So then why is 636,056 86 and not 96?

I can barely subtract and im a jr smh

This is very helpful for me because im not that good at math

How t f 185 is close to 125 than to 216? Ddd

It was on my recomendations. And i opened it bc i was so sure it would be an indian accent. Thnk god

Best

Who admits that he has a nice handwriting😄

I'm really scared of failing school

not working this trick try example : cube root of 18604

By using your trick it will be 24 but it is not the right answer

OP glitch, hope it gets patched soon!