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Number System || Divisibility Rule (LESSON-2) Tricks to Learn — Transcript

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0:05first of all
0:06thanks for being here in my youtube
0:08channel
0:09so in this lesson number two on the
0:11topic number system
0:13now we are going to learn one of the
0:15most very most important concept
0:17that is divisibility rule so friends
0:19listen here this
0:20divisibility rule is not only important
0:23for number system
0:24so this divisibility rule is important
0:26for the complete quantitative aptitude
0:29right because it's one of the rule that
0:31is common for
0:32all the numbers right easy calculations
0:35if some students making one minute for
0:38dividing some numbers
0:40if you know this divisibility rule you
0:42can able to crack the same
0:44number within two or three seconds for
0:47example let me take any number
0:48this one nine zero four
0:52so let me take this number one nine zero
0:54four so our target is to find by using
0:56which number we can divide this
0:591904 it is not easy right we don't know
1:02whether
1:03this number is divided by 13 whether
1:05this is divisible by 13
1:07or this number is divisible by 12 or 15
1:0916 17 etc
1:11but we can if you know the divisibility
1:13rule of all these numbers
1:15then definitely you can say that this
1:17number is divisible by 17
1:19right so this comes only in practice
1:22right
1:22so listen here we have to buy out all
1:24these divisibility rule no other way no
1:27other shortcuts
1:28but one thing we can separate the
1:30numbers into different
1:31categories we can separate the numbers
1:33into different different categories
1:35then if you start learning this
1:37divisibility rule that will be very easy
1:39i'm going to teach you this divisibility
1:41rule i'm just going to separate into
1:43different different categories and then
1:45we are going to learn the divisibility
1:46rule so that you can
1:48easily able to understand all the
1:49divisibility rule concepts
1:51so listen here after watching this video
1:53try to watch
1:54twice or thrice the same video so only
1:57then you can able to understand the
1:59concepts completely
2:00and then after watching this video take
2:03any numbers
2:04and try to find the divisibility rule of
2:06it so now let me move on to the
2:08divisibility rule
2:09so first which number is easy for the
2:12divisibility rule to learn
2:13is number five and number ten so these
2:17two numbers
2:18are first very easy to learn five and
2:20ten just here
2:21if any numbers right if any number
2:25that ends right the last digit is
2:28either 5 or 0. so got it
2:32for example let me take 1 0 5 yes so if
2:36they ask whether this 1 0
2:385 by which number we can divide this 1 0
2:415 so you can directly say that this
2:43number is
2:44divisible by 5. listen carefully if the
2:47last digit
2:48right if the last digit of a number
2:51given number
2:52is 5 or else the last digit is 0
2:56right then definitely those numbers will
2:59be divisible by
3:005. similarly if the last number
3:04right if any given numbers or the last
3:06number is
3:07only 0 right for example we can say
3:101 0 5 0 right so here you can able to
3:14see
3:14the last number is only 0 then
3:17definitely you can say that
3:18this number will be divisible by 10.
3:21got it easy or not right so this is the
3:24divisibility rule
3:25of 5 and 10. so listen carefully if a
3:29last number
3:30ends at 5 or else the last number ends
3:33at 0
3:34so those two numbers can be divided by 5
3:38right got it similarly if the last
3:40number
3:41ends at 0 so this number is also
3:43divisible by 5
3:45but you can directly able to divide the
3:47complete number by 10.
3:48so if the last number ends at 0 then it
3:52is divisible by 10.
3:53got it or not so out of these 18 numbers
3:56given numbers
3:57the first easiest divisibility rule that
3:59we can learn
4:00is for number five and number ten so
4:03friends got it or not right so what is
4:04the divisibility rule of number five or
4:06number ten
4:07so number five if the last number last
4:10digit
4:10right last digit of the given numbers it
4:13can be any numbers five digit or six
4:15digits just see
4:16five six zero five yes one zero five six
4:20zero five if they have given a number
4:22like this
4:23just look at the last digit of the given
4:25number so the last
4:26digit of the given number is 5 then
4:29definitely this
4:30complete number will be divisible by 5
4:34got it or not similarly if the last
4:36number is 0
4:38then the same number will be divisible
4:39by 5 or else
4:41this if a given number last digit is 0
4:45then the same number is divisible by 10.
4:47so this is called as a divisibility rule
4:50understood this is the divisibility rule
4:52for 5 as well as 10 right
4:54so we have learned the two numbers one
4:56is five
4:58and the second is ten so let me rub that
5:00value right it is easy right
5:01so without biating some students will
5:03sit and bypass from two to nineteen
5:05don't do that
5:06if you separate like this then learning
5:09the process learning this divisibility
5:10rule process will be very simple
5:13see next will be let me target the next
5:15number that is 2
5:17right number 2. next divisibility rule
5:20of number 2 will be very simple
5:22if any given numbers right if any given
5:24numbers
5:25the last digit just listen here the last
5:28digit of the given number
5:30should be even numbers or else
5:340 then the number will be divisible by
5:372.
5:37got it so let me take any number 1 6 5 2
5:41yes 1 6 5 2 just listen carefully what
5:44about the last number here
5:45so last number is 2 if the last number
5:48is
5:482 or else the last number it can be any
5:51even number for example let me take
5:53one six five eight it's an even number
5:55or not yes even number
5:57so if the last digit of the given number
6:00is
6:01even number or else the last
6:04digit of the given number is 0
6:07then both these numbers is divisible by
6:102.
6:11got it or not this is called as
6:13divisibility rule of two
6:15somebody's understood what is the
6:16divisibility rule of two the last
6:19digit sorry the last
6:22digit of the given number should be 2
6:26or else either it can be an any even
6:28number
6:29or it can be 0. so all these numbers
6:32can be divided by two it is called as a
6:34divisibility rule of two
6:36so once understood so now we have learnt
6:38what is the divisibility rule of two
6:42got it so finally we have learnt the
6:44divisibility rule for three numbers that
6:46is for
6:465 10 and 2. see how easy it is right
6:49so similarly next let me target the
6:52number 3
6:54see number 3 and number 9 will have a
6:56same category
6:58just listen here the divisibility rule
7:00of number three and number nine
7:02is you have to add you have to add
7:07sum of digits
7:10it's nothing but for example let me take
7:13any number
7:14340 342 right see 342
7:18we need to check whether this number is
7:20divisible by which of these numbers
7:22right
7:22so here what you need to do is you need
7:24to add
7:26all the digits right so 3 you can see 3
7:29plus
7:304 plus 2 got it or not sum of digits
7:33so 3 plus 4 plus 2 so what about the sum
7:364 plus 3 will be 7 7 plus 2 will be 9
7:40so after adding all the sum of digits we
7:43got the
7:44number 3 so sorry so we got the number 9
7:47so now check whether this 9 is divisible
7:50by 3 or not s it is divisible by 3
7:53so if the number is divisible by 3 then
7:56we can say that the complete number
7:58will be divisible by 3. so friends
8:00understood and we want some other
8:02example questions for example
8:04let me take 162 right
8:07so we need to check whether it is
8:08divisible by 3 or not so what you need
8:10to do
8:11you need to add all the digits
8:141 plus 6 will be 7 7 plus 2
8:17will be 9 so the last number after
8:20adding all the digits we got 9
8:239 is divisible by 3 or not yes it is
8:25divisible
8:26if 9 is divisible by 3 then we can say
8:29that
8:29the complete 162 will be divisible by 3.
8:33the same logic is for number 9 also
8:36let me take any other example we can go
8:38with 2
8:394 3 2 4 3
8:42so just see here they have given a
8:44number that is 2 4 3 2
8:464 3 and we need to check whether it is a
8:48divisible by which of these numbers
8:50so what you need to do is you need to
8:52add all the digits right
8:542 plus 4 plus 2 will be 6 6
8:57plus 3 will be 9 9 plus 2 will be 11
9:0111 plus 4 will be 15 15 plus 3 will be
9:0418
9:06so after adding all the digits we got
9:0818.
9:09so 18 is divisible by 9 or not s it is
9:13divisible by 9.
9:14if this number 18 is divisible by 9 then
9:17we can say that this complete number
9:20is can be divided by n got it
9:23in case if we are adding all the numbers
9:25if we are getting only 17
9:28then definitely this number cannot be
9:30divided by
9:319 as well as the same number cannot be
9:33divided by 3
9:35got it so when you should say that this
9:37number is divided by 3 or 9
9:39if the sum of digits after adding all
9:41the sum of digits
9:42right the final answer should be divided
9:45by 3
9:46or the final answer should be divided by
9:489 right
9:49if it can divide by 3 and if it can
9:51divide by 9 then we can able to say that
9:54the given number is divided by 3 as well
9:56as 9.
9:57so this is called as a divisibility rule
10:00of three
10:00and divisibility rule of 9 easy or not
10:04it's very easy right so now we have
10:06learnt another two numbers that is a
10:08divisibility rule for another two number
10:10that is for 3
10:11as well as 9.
10:15so next will be let me target
10:18the next number for four and eight this
10:22this is also very easy four and eight
10:25see if you take the numbers four and
10:28eight
10:28the last two digit any numbers for
10:31example one
10:32six two four got it in the given number
10:35if the last two digit of the number
10:38is divisible by four check only 24
10:4224 is divisible by four or not yes six
10:44fours are 24
10:46so we can say that if the last two digit
10:49of the given number is divisible by four
10:52then the complete number will be
10:54divisible by four
10:56so friends got it easy or not just
10:58listen here if the last
11:00two numbers right if the last two number
11:03is divisible by four then the complete
11:06four numbers all the given numbers that
11:08complete set of number
11:09can be divided by four it can be divided
11:11by four got it it's a divisibility
11:14rule of 4 as well as divisibility rule
11:16of 8 should be the last
11:183 digit of the number so whatever number
11:20be if the last
11:223 digit of the number is divisible by 8
11:25then complete number can be divided by
11:28eight
11:28so friends got it or not so this is the
11:31divisibility rule for
11:32four as well as divisibility rule for
11:35eight
11:36easy divisibility rule for three and
11:38nine is what you need to add
11:40some of the digits and final answer you
11:42need to check whether the final answer
11:44is getting divided by three or nine
11:46but when you take four and eight what
11:48you need to do for number four you need
11:50to check the last to two digit
11:52if the last two digit is divisible by 4
11:56then the complete number will be
11:58divisible by 4.
11:59similarly if the last 3 numbers is
12:02divisible by 8 then the complete given
12:05number
12:06will be divisible by 8. so friends
12:08understood or not so this will be the
12:10divisibility rule for four
12:11as well as eight got it so finally we
12:14have learned lot of numbers now
12:15now you feel right this divisibility
12:17rule will be very easy
12:22ok so now let me target another set of
12:25numbers
12:26that will be very simple just see here
12:28when you take number six
12:30right number six are 12 yes
12:3312 14 15
12:3818 right so let me take all these
12:40numbers 6
12:426 12 14
12:4615 and 18. see for all these numbers you
12:49don't want to learn
12:51a divisibility rule separately why
12:53because
12:54for six right for what you need to do is
12:57if a number right if a number
12:59is getting divided by two as well as the
13:03same number is getting divided by 3
13:05then we can say that the number will be
13:07divisible by 6
13:09also so friends got it or not let me
13:11take one example
13:12so let me take example as 123.
13:16sorry 120 120s
13:206 okay let me take the number 126
13:23right so just see here this number 126
13:27can be divided by 2 yes or no because
13:30the last
13:31digit of the given number is 6 even
13:33number so it can be divided by two
13:35so similarly if you add all these
13:37numbers six plus two
13:39eight plus one will be nine so sum of
13:41digit is nine
13:42so nine will be divisible by three so
13:44the same number
13:46can be divided by 3 also yes or no if a
13:49number
13:50if the given number is divisible by 2
13:53as well as the same number is getting
13:54divisible by 3.
13:56so these cases right if a same number is
13:58divisible by 2 as well as 3
14:00then we can surely say that this number
14:03126
14:04will be divisible by 6 also you can
14:06directly divide by 6
14:086 2s are 12 1 6 are 6 21
14:11yes or no right got it so remember that
14:13the divisibility rule of 6
14:15is what if a number getting divisible by
14:182 as well as the same number is getting
14:20divisible by 3
14:22then we can say that the number will be
14:23divisible by 6. so similarly you can
14:26learn all these right
14:27so 3 and 4 if a number is divisible by 3
14:31as well as the same number is getting
14:32divisible by 4 then we can surely say
14:35that the given number
14:36will be divisible by 12 easy or not so
14:38now it is for 14
14:407 and 2 got it so 15
14:43503 see how easy it is for 18
14:47902 got it if a number
14:51is getting divisible by 2 as well as the
14:53same number is getting divisible by
14:559 then we can say that the complete
14:57number can be directly divisible by 18.
15:00just see how easy it is initially it was
15:03difficult by seeing 19 numbers
15:05but now we have learnt a lot of
15:07divisibility rules
15:09by separated into different different
15:10categories got it
15:12so finally we have how many numbers
15:15remaining one two three
15:16four and five so totally we have five
15:19numbers
15:19remaining right so these five numbers
15:22again
15:23we can use one method called escalator
15:26so by using that method we can easily
15:29able to learn
15:30the divisibility rule of all these
15:31numbers so let me move on to that
15:33so before that take a note of it right
15:35it is important always
15:37that's what i am saying try to watch the
15:39video again
15:40and take a proper note because this will
15:43help you
15:44for the complete quantitative aptitude
15:46section right for the easiest
15:47calculations so here the next set will
15:50be 7
15:5113 17 and 19 right so except this 11 we
15:54are taking the remaining numbers
15:56the 7 13 17 and 19. so just see here
16:00what i am going to do here is
16:02let me take the first number that is 7
16:03we know we are going to learn
16:05the divisibility rule for someone for
16:07example
16:08they have given a number as 343 they
16:10have given 343
16:11and we need to check whether this number
16:13is divisible by someone or not
16:15so what you need to do here is you need
16:17to concentrate on the last
16:19digit right so last digit is what 3 year
16:22you need to multiply this 3 by 2 just
16:25listen carefully
16:26you need to multiply this last digit of
16:29the given number by 2
16:31so 3 into 2 is what 6 got it
16:34so now the remaining two numbers are
16:37what 34
16:38so you need to subtract the 6 with 34
16:41so resultant will be 28 so now
16:45this 28 is divisible by 7 or not yes it
16:48is divisible by 7
16:497 4's are 28 so if 28 is divisible by 7
16:54then we can say that the complete 343
16:57will be divisible by 7. so friends
16:59understood i can explain again just see
17:01here
17:02in the given numbers whatever number be
17:04in case it can be four digit or five
17:06digit whatever number b
17:08you have to target the last digit of the
17:10given number
17:11and you need to multiply by what you
17:13need to multiply by two
17:15so three into two is what 6 so i have
17:17written 6 here
17:19and what about the remaining numbers
17:20remaining number is 34
17:22in case if it is a 4 digit number the
17:24remaining number will be 3 you
17:26have to take all the 3 numbers got it so
17:28here the remaining number is 34
17:31you have to subtract this 34 with 6
17:34resultant will be 28 now check whether
17:37this number 28
17:39is divisible by 7 yes the number 28 is
17:42getting divisible by 7
17:43then we can say that the complete 343
17:46will be divisible by 7.
17:48friends got it how easy it is right so
17:50it's a divisibility rule of 7
17:53so similarly our next target
17:56let me go with 17. so just see here 17
17:59is also a same scenario
18:011904 what about the last digit
18:04the last digit is what 4 here you have
18:07multiplied by 2
18:08but here you have to multiply by 5 got
18:11it
18:115 into 4 is what 20 what about the
18:15remaining numbers
18:16is 190 so subtract with 190
18:19resultant will be 170 now check
18:23whether we can divide 170 by 17 yes it
18:26is divisible yes or no
18:28we can divide 170 by 17. so finally we
18:30can say that
18:31this complete number 1904
18:34can be divisible by 17 understood
18:37friends
18:38this is the divisibility rule for 7 and
18:4017
18:41for 7 you need to multiply by 2 for 17
18:44you need to multiply by
18:455 but in both the cases you have to
18:48subtract that is important
18:50right because in these two cases that is
18:52for 39 19
18:54you will add got it so this is the
18:57divisibility rule for 7 and 17
18:59you have to take the last digit for 7
19:02you need to multiply by 2
19:04for 17 you need to multiply by 5 and you
19:06need to subtract with the remaining
19:08numbers
19:09and you need to check the resultant
19:11number is getting divisible by 17 or not
19:13so here 170 by 17 so the resultant
19:17number is divisible by 17
19:19so finally we can say that the complete
19:21number will be divisible by 17.
19:23so now let me target 13 and 19. see here
19:26if you go with 19 again everything is
19:28similar process
19:30just look at the last digit last digit
19:32is what one
19:33you need to multiply by 2 right the same
19:36way you need to multiply by 2
19:381 into 2 will be 2 what about the
19:40remaining digit
19:41is 36 in those two cases we have
19:44subtracted but in this case you need to
19:46add
19:4736 plus 2 will be 38 so now check
19:50whether number 38 is divisible by 19
19:53yes 2 times it is divisible so finally
19:56we can say that
19:57this complete 361 will be divisible by
20:0019.
20:01so the last is 13 right so similarly you
20:04have to look at the last digit of the
20:06number is 5
20:07you have to multiply this by 4 5 into
20:104 is 20 what about the remaining digits
20:1432 similarly you have to add right so 32
20:17plus 20
20:18will be 52 so 52 is divisible by 13 yes
20:22it is divisible
20:23so finally we can say that the complete
20:25number will be divisible by 13.
20:28so this is the divisibility rule for 13
20:31and divisibility rule for 19.
20:33so friends got it or not right so it
20:35takes time to learn again i'm saying it
20:37is not
20:38easy but if you if you for example if
20:41you work
20:42two or three hours for learning this
20:43divisibility rule
20:45then when you compare to other students
20:47you can able to
20:48calculate fastly calculations will be
20:50very easy simplification approximations
20:53and major quantitative aptitude
20:55questions like
20:56time and work time and distance on those
20:59cases
20:59the cancelling part will be very easy so
21:02just spend your time two to three hours
21:05or even
21:06five hours six hours to learn this
21:08divisibility rule properly
21:09so if you learn this divisibility rule
21:12again i am saying
21:13you your calculations will be very very
21:15simple and easy
21:16so friends got it so this is the
21:18divisibility rule of 7 13
21:1917 and 19. here we have subtracted for
21:22two numbers
21:23and here we have added two numbers and
21:25we are concentrating only on the
21:27last digit of the numbers right so two
21:30to three times if you practice
21:32automatically you can buy at it right so
21:34the last will be the number 11.
21:36so number 11 is easy so this this method
21:39right is called as
21:40escalator something they used to say in
21:42mathematics so those cases are not
21:45needed right
21:46because only if you are preparing for
21:48any schools 10 standard nine standard
21:51for those cases we have to learn all
21:53those method but it is enough right if
21:55you understood the logic that is more
21:57than enough
21:58so now the last number is 11 right so
22:01let me take any example question
22:03so 9 1 7
22:064. so let me take this example question
22:09as 9174
22:10so the divisibility rule of number 11
22:13will be very easy
22:14what you need to do is you need to add
22:16right you need to add
22:18all the odd digits and you need to add
22:21all the even digits and you need to find
22:23the difference
22:24and you need to check whether the final
22:26answer is getting divisible or not just
22:28see here
22:29what about the odd digits here number
22:31nine is the first digit
22:32number one is the second digit seven
22:35will be third digit
22:36four will be fourth digit got it or not
22:38so here you
22:39have to add all the odd digits add it so
22:42first
22:439 is the odd digit 7 is the odd digit so
22:46if you add 9 and 7
22:47it will be 16. now add all the even
22:51digits
22:52so 2 1 and 4 will be 5
22:55got it so now find the difference 16
22:57minus
22:585 will be 11. so now check whether
23:01this number 11 is divisible by 11 or not
23:04yes it is getting divisible
23:06so finally we can say that this complete
23:08number
23:099174 will be divisible by 11. got it
23:12so this is the divisibility rule of 11.
23:16yes got it on our friends whatever
23:17number b right
23:19for example let me take six three nine
23:22one
23:23five four right got it so if we need to
23:26check the divisibility rule of 11 what
23:28you need to do is
23:29you need to add all the odd digits 6
23:32plus
23:329 plus 5 got it and then you need to add
23:36the even digits so 3
23:37plus 1 plus 4 so after adding the odd
23:40digits
23:41even digit you need to find the
23:42difference so for example
23:45if you are getting 33 check whether the
23:47number 33 is divisible by 11 yes it is
23:49divisible by 11.
23:51if this number is divisible by 11 then
23:53the complete number will be divisible by
23:5511. so this is called as
23:57a divisibility rule of level so go
23:59defense so finally
24:01we have learned the divisibility rule of
24:03all the numbers
24:04very simple and very easy so spend your
24:08time right
24:08again i am saying spend four or five
24:10hours of time for learning this
24:12diversibility rule
24:14so when if you learn the divisibility
24:16rule properly then you
24:18can solve you can able to solve most of
24:20the tough level calculations easily
24:23that comes only in practice so i will
24:25teach all those
24:26shortcuts later on on my youtube channel
24:28but before that you need to learn this
24:30diversibility rule
24:32so again i am saying after learning this
24:34divisibility rule
24:35take many numbers as much you can and
24:37start solving it
24:38by checking which of this divisibility
24:40rule is applied
24:41so only if you practice more question
24:43you will feel convenient on this
24:45divisibility road
24:46so friends got it so thank you so much
24:48for watching this video
24:49and if you really like it share the
24:51video to your friends
24:52those are preparing for the competitive
24:54exams so thank you so much for watching
24:56it
24:57bye

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This page contains the full transcript of Number System || Divisibility Rule (LESSON-2) Tricks to Learn by Feel Free to Learn, generated from the public captions YouTube serves with the video. The transcript has 4,292 words across 698 segments, with the original timestamps preserved so you can click any line to jump to that moment in the embedded player.

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