Find the Cube Root of 216 without a calculator

I use a factor tree in order to find the cube root of 216.
This video is part of a playlist of finding the cube root of numbers 1 through 50

[Ashlyn-magazines]

THAT WAS so simple yet easy to understand thank you so much!! I have an exam tomorrow wish me luck 🍀

[MrCoolio]

Brilliant thank you so much! This was the exact question in my IGCSE material. Explained brilliantly and a nice sign off at the end :)

[lechaiku]

That's a good method for solving cube roots.

However, there's almost immediate way to deal with that problem.
Why don't teach the students the simplest and logical steps to obtain the required result.

The students only need to learn a few things:
1.
the last digits of cubes of 1 to 9

1 1 (last digit)
2 8
3 7
4 4
5 5
6 6
7 3
8 2
9 9
and, of course, 0 0

we see that 0, 1, 4, 5, 6, and 9 have always the same last digits (consecutively)
but 2, 3, 7, 8 have always the compliment to 10 (2 +8 / 8 +2 and 3 + 7 / 7 +3)

2.
the number of digits in the cubes

1-digit numbers have at most 3-digit number in its cubes
2-digit numbers have at most 6-digit number in its cubes
3-digt numbers have at most 9-digit number in its cubes

informally we can say that 1 digit "can make only" 3 digit, right?

so
cube√ 216 3-digit number 1-digit number
6 is the last digit 6 the last digit
cube√ 216 = 6

4-digit number 2-digit number
5 is the last digit 5 the last digit

now we ignore the 3 last digits (375) and consider only the first digit which is 3
and 3 is more than 1(1^3) and less than 8 (2^3) so
the first digit must be 1 and the last digit must be 5.

cube√3375 = 15

3.
The students need also to remeber the cubes of 1 to 9
it is very easy to memorize by students
1 1
2 8
3 27
4 64
5 125
6 216
7 343
8 512
9 729

It is so easy, isn't?

[eliashailu]

Bro you are the best easy not complicated and not a fake simple solution like those tiktoks thanks you made my day❤

[Mingorix]

man how does this video have dislikes its literally the best way to explain this in an extremely understandable way.

[gachatops]

out of chatgpt, microsoft math solver, and other websites, this video is the only thing that helped lol

[menilu]

Thank you so much. I have watched so many video that would only show how to do simple cube roots. Thank you 🙌

[fardboy]

My brain went boom the dots are connected amazing content

[nkzamrud]

This is prime factorization of the number and taking cube root 👍

[Learner]

Thank you so much sir you are awesome thanks a lot 🙏🙏

[sammyjoy]

thank you for reminding us to be kind ❤

[Justincowan]

good video man keep up the good content

[siddharthasingh]

Very lengthy method. You should try vedic method, it's really quick

[LoganStargazer]

This is a specific video on how to calculate the cube of 216. What if the number is *not* 216? Tough beans I guess. lolol

[craftcrewtv]

How can I get prime numbers if the number under cube root itself is a prime number? And what to do with the numbers that aren't in triplets? You missed out a lot of important details

[MarkerHealthcliff]

second also these videos suck because I don’t even have science class -_-