Divisibility Tests and their application on finding Prime numbers.
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- čas přidán 13. 07. 2024
- In this video we will learn divisibility tests from 2 to 13 and will learn their application on solving an important class of questions which comes in a lot of examinations.
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I hope it helps !
Can you give me a link to your video about multiplication shortcuts?
there are a lot of videos on the channel on that.
I have a question bhaiya!!! who invented this awesome divisiblity tests? I remember my teacher teaching me in 3rd grade!
And can you please help me? I am in 10th and am really very nervous for my exams since we have a very huge syllabus in every subject. Can you please help me in maths? like any videos to simplify complicated chapters for class 10th students for this year?
@@trisha.718 hello bhai i am from india too
連除法的基本上功教到了。無得頂。多謝。十分重要。多謝。。。
wow ! this is clear , concise ,and complete , always you make me want to learn more !
Tbh, you only need to test for 2,3,5,7,11,13 because if they're divisible by 4,6,8,10,12 then they're divisible by 2 and if they're divisible by 9 then they're also divisible by 3
yes , for this application, these are enough .
@@mathOgeniusthen 17..?
This was very informative. Thank you for making this video.
Loved it
Your class make me to get more knowledge (maths)🤩
I wish you uploaded it yesterday, i had my maths exam today....
It helps alot
I HAVE AN EXAM ON THIS TOMMOROW THANK YOU SOO MUCH
On the 157. You shouldn’t need to check for 13 as 13 squared is 169. If any number below 169 is divisible by 13 then you will have already found a divisor! Another interesting for 13. Multiply it by 7 and then 11 it will be a multiple of 1001. Example 273 x 7 x 13 gives 21021
You make good math video
Hey. U only need to check divisibility for 1 to square root of that number. For example: u want to know if 101 is prime. Square root of 101 is 10.1(suppose), u only need to check divisibility for 1 to 10 . And also u don't need to check for even number bcoz if the number is divisible by even number then it will also be divisible by 2 . So it can't be prime(except if the number itself is 2).
So for 101 we only need to check for 2,3,5,7,9.
The reason is simple.
Suppose the number is 100.
Square root of 100 is 10.
So. 10x10 = 100.
(Less than 10) x (Less than 10) = Less than 100)
(Greater than 10) x (Greater than 10) = Greater than 100
So two numbers will only make 100 when one is less than 10 and the other is greater than 10.
So if there is an integer less than 10 which divides 100 perfectly then there must be an integer greater than 10 which also divides 100 and together they make 100 when multiplied by each other.
And if there is no number less than 10 which divides 100. Then there can't be a number greater than 10 which does the same.
I hope this is helpful
What is number is larger
What if
I will never struggle with finding prime numbers any more!!!!!!!!!😅
Can you please upload a vedio on chika's rule
How to cube 2 digit number pls, make a video about it.
Checking if 147 is divisible by 7:
7×2=14
14-14
0 ans
Prime no generally in the form of 6n+1 or 6n-1 for >3
How I do is test for 2 by add that number and test for 2. Similarly add other number individually and test for 3 , 5 and 7 . Finally 13. Much faster
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Nice comment bro I am always with you thinking about this methOgenius sir
Great comment I am always with you
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Division by 11 is easier if you subtract the last digit by the rest
Example 121 = 12-1 =11
In the manner in which the ( Aaradhya Gujar ) commenting and the mathOgenius sir is talking I think that you both are brother because Aaradhya always writing a word brother and a friend
Anyway I don't care because I hope that if you are both are not brother but in which manner and you both are talking I hope that you were always be a friend or a brother not in real life but in online you are always be brother I wish to God and pray to God to make your friendship or family nice always together
5:37
Why u added 5+2 while
5 is not a even number..?
Can't believe 2,3,5,6,11 my math sir told Were these
❤💯🙂
Please do you upload English speaking classes please 🥺🥺🥺🙏🙏🙏
we learnt it in 3rd grade!!!
*You can invent your own divisibility tests for the next prime number or use algebra to verify the existing ones* . Here is how -
Assume A is a positive integer and b is a single digit. So, Ab is mathematically (10A+b). To invent your divisibility test of 7 or 13 or 17 -
(10A + b) = 10 (A - 2b) + 21b. Since 21 is a multiple of 7, you just need to check if A - 2b is a multiple of 7 (10 is ignored because it's not a multiple of 7 and has no common factors).
(10A + b) = 10 (A + 4b) - 39b. Since 39 is a multiple of 13, you just need to check if A + 4b is a multiple of 13 (10 is again ignored since it's not a multiple of 13 and has no common factors).
(10A + b) = 10 (A - 5b) + 51b. Since 51 is a multiple of 17, you just need to check if A - 5b is a multiple of 17 (10 is again ignored since it's not a multiple of 17 and has no common factors).
So, divisibility test of 17 is the same as 7 except multiply the last digit by 5 instead of 2 and check if the remaining (smaller by 1 digit) number is a multiple of 17. Repeat as needed if its not small enough. *Thank you for sharing your videos. I did not know the divisibility test of 7 but in an attempt to verify it's correctness, I was able to invent my own test for 13 which later matched as your video continued into the next prime. I added divisibility test of 17 to prove that this method of inventing new divisibility tests works for any next prime number* .
(10A + b) = 10 (A + 2b) - 19b. Since 19 is a multiple of 10, you just need to check if A + 2b is a multiple of 19 (10 is again ignored since it's not a multiple of 19 and has no common factors).
So, divisibility test of 19 is the same as 7 except *ADD* instead of subtracting twice of last digit and check if the remaining (smaller by 1 digit) number is a multiple of 19. Repeat as needed if its not small enough. Example: 4446 => 444 + 12 = 456 => 45 + 12 = 57 => 5 + 14 = 19 which is a indeed a multiple of 19. Is *437* a prime number ?
💖💖🙂🙂🙂
I Tried 97632 And It's Camed 11 But It's Not Divisible By 11.
Yar 🥺🥺🥺🥺💕
WHAT DIVISIBILITY BY 3 MY MATH SIR TAUGHT ME 1 YEAR AGO
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Hello, could you help me with this problem, so that I can find free time to dedicate to mathematics, I have this homework that is part of my routine and I want to see how I could make it less stressful or tiring, I have 11 subjects that I did in high school and these are; Chemistry, Social Sciences, Mathematics, Biology, Philosophy, Plastic Arts, Language, Physics, English, Music, Religion because my school is Catholic, I already saw your intercalation video but I don't know how I could intersperse these subjects and get good scores in my exams In addition to correctly learning each topic that is presented to me, I also saw a video of a youtuber called Fayelinn but her way of organizing the topics is very masochistic and unnecessary, I also take a private English course that lasts an hour and 30 minutes from 5 -6:30 pm, besides that I also help my mother in her work washing dishes that takes me about an hour, in short, if you can help me with my hour of self-study, that is, my study sessions to be able to assimilate each lesson correctly I would like each subject since I have tried to do it but I don't know how to do it since the videos I see are more aimed at the university. Anyway, to complement my class schedule is like this:
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Every afternoon from 5 to 6:30 pm I have English classes from Monday to Friday.
[5:27 p. m., 28/9/2022] Villarroel Churqui: and all the weekend i do my homework of this week
157
I didnt understand divisible by 11 even odd?
See imma give you an example .take this no as example : 5678934
Now from 4 start naming the number s as odd and even O=odd and E=even
5 6 7 8 9 3 4
O E O E O E O
Now add the odd numbers and even numbers
Odd=4+9+7+5=25
Even=3+8+6=17
Subtract the numbers now
25-17=8
Is 8 divisible by 11
No
So your number 5678934 is not divisible by 11
@@Arushiii_corethank you for that!
B k
Bro try my best but I can't learn math why
then I think you have to go back to basics and start building up from there.
grab primary ncert books
You are Indian or foreigner
Indian
Who is average student here
Attendance