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Tagged: DigitSum
 This topic has 40 replies, 16 voices, and was last updated 11 months, 1 week ago by UshaT.

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January 18, 2021 at 7:49 pm #28122PasyanthiKeymaster
Please use this thread to post your questions/Comments/Impressions/Learnings from topics covered in week 2 video lessons
Happy VM learning 🙂

January 19, 2021 at 10:53 pm #28164Basa Mallika GogulamudiParticipant
Hi Ken,
Digit sum concept is really interesting and I would like to explore more.
I have few queries.
1. Are digit sum and casting out 9 based on any Vedic sutra(s)?
2. Do we have any other applications of digit sum other than verifying answers and divisibility checks?
3. Do we have any applications of number patterns and Vedic designs?
Thanks.

January 20, 2021 at 7:56 pm #28175KennethWilliamsKeymaster
Hi Mallika,
Thanks for the questions.
1. Finding a digit sum is based on ‘By Addition’, Sutra 7, and casting out 9s is based on Sutra 5: ‘If the Total is the Same it is Zero’.
2. You will see more applications. It can be used in algebra too and for finding a missing digit or coefficient.
3. Patterns are always useful as they lead to more general concepts and ways of extending them and seeing connections with other patterns. It has been said that mathematics is all about the study of patterns. Fot the Vedic Square designs I am not aware of applications other than the fun in generating patterns: someone should look into this 🙂


January 20, 2021 at 7:45 am #28165Anupama CherukuriParticipant
Hi Ken,
I have the same question do we use digit sum in any other applications?
For. Ex.999 – the answer is 9 or 0.
So if we use digit sum in any other applications how can we know which digit we have to use 9 or 0.
January 20, 2021 at 8:06 pm #28176KennethWilliamsKeymaster
Hi Anupama,
See my reply to Mallika above.
For 999 the digit sum is 9 or 0.
There are many other times that we get 2 or more answers to a mathematics question. For example in solving quadratic equations we generally get 2 solutions.
There will never be any contradiction in using either 9 or 0. Using either will give the same answer. It’s like saying the time is 1pm, or the time is 13:00 hours – they are equivalent.


January 20, 2021 at 8:51 am #28166Maurice PerryParticipant
Can you give me the web address to learn more about Russian Peasant Multiplication?

January 20, 2021 at 8:08 pm #28177KennethWilliamsKeymaster
Hi Maurice,
I suggest you google it.
The other word used in that video was ‘chisenbop’. That too you can google to find out more. 
January 21, 2021 at 3:19 am #28188Maurice PerryParticipant
Thank you Ken. I wasn’t sure how to spell it.


January 20, 2021 at 11:24 pm #28184SatyaParticipant
Hi Ken,
Thank you for providing more details about digit sums through this thread – Definitely an interesting and fun topic to learn. In the 2nd video during The Digit sum check, it was mentioned that the sum verification may not be correct always as altering placement of digits in the same number might give same digit sum but can change the actual answer like wrong answer can still give the same digit sum etc.
So how confidently can we use this method and why is this method considered to be used with this uncertainty?
Thanks
Satya
January 22, 2021 at 6:24 pm #28240KennethWilliamsKeymaster
Hi Satya,
It is still worth using the digit sum check. Together with checking the first and last digits it means we can usually be highly confident of a result if not absolutely certain. Thanks to Mallika for her comments.
We will soon see another digit sum checking device, based on 11 rather than 9.


January 21, 2021 at 2:22 am #28185Basa Mallika GogulamudiParticipant
Thanks Ken for the clarification.
Yes, Patterns are very useful in analyzing, predicting, forecasting and in giving projections.
Thanks Ken for all your work and contributions in VM. VM has changed my son’s attitude towards maths. I can’t thank you enough for that.

January 21, 2021 at 2:32 am #28186Basa Mallika GogulamudiParticipant
Hi Satya,
Even though digit sum checking doesn’t spot the error all the time, it is very handy. I have taught this to my 10 year old son. It has spotted errors many times especially in 4 digit by 4 digit multiplications. As 4 digit by 4 digit multiplication is not easy to verify answers using inverse (division) operation.
Thanks.

January 21, 2021 at 3:11 am #28187SatyaParticipant
got it. Thank you Mallika

January 21, 2021 at 10:13 am #28189Savita P KulkarniParticipant
Hi friends,
This week i was late in starting.
I just finished video 5 ( first video for week 2) and I had fun practicing the digit sums, casting nines, digit sum puzzels, and divisibility tests for 3, 9. 6, and 15, and remainder on division by 9.
Thanks to Mallika, Satya, Maurice, Anupama for starting interesting conversations here and to Mr. Ken for answering the querries and putting more light on patterns, applications on digit sums, providing alternate examples like 1:00pm is same as 13:00hours.
Thanks, 
January 21, 2021 at 5:38 pm #28217Savita P KulkarniParticipant
Hi,
After watching 6th video, I am amazed by the uses of digit sums and the different methods to check errors. i wonder if there is any connection between Vedic math/ Vedic design/square and rangoli wherein patterns, points, and lines make such wonderful and artistic designs, may be….
Thank you,
Savita 
January 22, 2021 at 10:21 am #28236Anupama CherukuriParticipant
Thank you so much for explaining. After Lesson 6 I understood more clear way 0 or 9 there will be no contradiction to the solution.
In the Practice HW book color the Vedic grid I am just curious to know if there are any other observations.
My observation is all the digits except 3,6 and 9 … the digit repeats 6 times. For 3 and 6 – digit repeats 12 times and 9 repeated 18 times. 
January 22, 2021 at 1:30 pm #28237Savita P KulkarniParticipant
Mental multiplication seems difficult at first, but with practice it gets easier and it is fun to solve.I am going to read more about ‘chisenbop’, thank you Maurice for initiating the discussion about it.

January 22, 2021 at 4:25 pm #28238Shikha DhingraParticipant
Hi!
Thanks everyone for their valuable inputs. I am really excited to learn about nine point circle, casting out nine and checking errors using digit sum method . It really saves a lot of time spent during rechecking. I also taught this method to my 12 year old .He told me to give me more practice questions so that he can use this method. The practice homework assignments provides ample practice of particular method.
Thanks 
January 22, 2021 at 9:16 pm #28241KennethWilliamsKeymaster
Please note that there is a question missing in the Week 2 Test. This is:
Use doubling and halving to find: 35 x 74.This should follow question 13.
So please note that questions 14 and 15 refer to this doubling and halving method. 
January 23, 2021 at 2:44 am #28242Basa Mallika GogulamudiParticipant
Hi All,
I want to share my observations.
We can get a remainder on division by 3 using digit sum.
For division by 3 :
As we all know if the digit sum of a given number is 3 or 6 or 9, then the number is divisible by 3 and the remainder will be 0.
If the digit sum of a given number is less than 3, then the digit sum will be the remainder.
Examples :
28 divided by 3 = 9 rem 1, digit sum of 28 is 1 and remainder is also 1.
812 divided by 3 = 270 rem 2, digit sum of 812 is 2 and remainder is also 2.If the digit sum of a given number is greater than 3, we have to repeatedly subtract 3 from the digit sum until the answer is less than 3 and that answer will be the remainder.
Examples :
25 divided by 3 = 8 rem 1, digit sum of 25 is 7 and if we subtract 3 twice from 7 we get remainder as 1.
98 divided by 3 = 32 rem 2, digit sum of 98 is 8 and if we subtract 3 twice from 8 we get remainder as 2.This holds good for any number to get a remainder on division by 3 using digit sum.
I am checking if there are any patterns to get a remainder for division by 6 using digit sum but no luck so far.
Thanks.

January 23, 2021 at 3:57 pm #28296KennethWilliamsKeymaster
Very interesting Mallika. Your observations are correct.
I’m glad to see you are researching like this.


January 23, 2021 at 1:46 pm #28293Savita P KulkarniParticipant
Hi Mr. Kenneth,
There was allowed second attempt for quiz 1 only. But for quiz 2, I am able to go for the second attempt. Shall I take it ? Is it allowed?
Thanks, have a good weekend,
Savita
January 23, 2021 at 3:55 pm #28295KennethWilliamsKeymaster
Hi Savita,
The Pasyanthi Team said there is only 1 attempt after test 1. So I suspect you would not be able to complete a 2nd attempt. Try it if you like. But as you say it will be the same questions.


January 23, 2021 at 3:27 pm #28294Savita P KulkarniParticipant
The second attempt has the same questions.

January 23, 2021 at 8:52 pm #28612Fabio ZanattaParticipant
Hello everyone,
I have a question on Russian multiplication.
I understand the method as follow:
I consider the multiplication 8×6=48. The 8 (4th finger on the left hand) have 3 fingers at his left. The 6 (2nd finger on the right hand) have only 1 finger at his right. I sum 3+1=4 and I have the first result digit.
Now, I multiply 4×2=8 because the 8 is the 4th number and 6 is the 2nd and I obtain the second result digit.
This is correct?

January 23, 2021 at 11:43 pm #28614KennethWilliamsKeymaster
Hi Fabio,
The first part is ok: 3+1=4.
The 8 comes from 2×4 where 2 is the touching finger on the left and the one below it, and the 4 is the touching finger on the right plus the 3 fingers below that.


January 24, 2021 at 1:10 am #28615Fabio ZanattaParticipant
Thanks mr. Ken for the answer.

January 24, 2021 at 8:47 pm #28830Amara DeepthiParticipant
Hi Ken,
I was doing the homework manual. In that Lesson 3, Practice E, 11th problem – the question says there are 5 two figure numbers below 40 whose digit sum is 1. Bu there are only 4 numbers – 10,19,28 and 37. Even in the answer they didn’t mention the 5th number. Kindly clarify.
Regards,
Deepthi

January 24, 2021 at 9:21 pm #28831Basa Mallika GogulamudiParticipant
I also noticed it. It has only 4 combinations. This could be a printing mistake.


January 24, 2021 at 9:22 pm #28832KennethWilliamsKeymaster
Hello Deepthi,
Well spotted !
You are right there are only 4 answers, not 5.

January 25, 2021 at 9:39 pm #28858Amara DeepthiParticipant
Thank you for the clarification Ken


January 25, 2021 at 4:12 am #28834Rameshwari G SreedharParticipant
In Week 2 , lesson onedigit sum puzzle, What is the and for the last qs please? digit sum=4, one is 3 times the other?

January 25, 2021 at 5:06 am #28835Rameshwari G SreedharParticipant
I guess the ans is 13 or 31, please ignore my qs


February 4, 2021 at 3:34 am #29894Seth KinkadeParticipant
Are there circumstances, such as in multiple digit addition, where the traditional Western approach of calculating right to left is superior, or would you recommend attempting to retrain and teach left to right for all calculating?

February 4, 2021 at 7:10 am #29896KennethWilliamsKeymaster
Hi Seth,
I hope you are not thinking that in VM we only calculate from left to right, because that is not so. Both are useful and the Vedic mathematician chooses the best method at any time: right to left or left to right.
Certainly right to left is better sometimes, and educationally it makes sense to learn right to left first of all because we start with learning about units before tens and so on.
We do focus more on the left to right direction on this course, but that is because people are very familiar with right to left methods already. And as you will see there are many advantages of working that way.


February 4, 2021 at 8:33 am #29897Seth KinkadeParticipant
Thank you, Ken!

February 14, 2021 at 2:21 am #30812Angelina Claire Stanness MetcalfeParticipant
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Great questions above and I found answers I was also looking for.
Thanks everyone

February 14, 2021 at 2:55 pm #30895VenkatKoppakaParticipant
a2 b2
c1 b1

February 16, 2021 at 2:53 am #31133Preeti PathakParticipant
Hello,
Enjoyed week 2 videos lessons, digit sum concept, calculating from left to right .
In Vedic Maths ,we can calculate from left to right or right to left whichever we find useful , is very helpful .Its flexible. In the beginning, calculating from left to right seems difficult but after practicing ,we can do it in a better way.
Thanks

February 16, 2021 at 3:37 pm #31153UshaTParticipant
<sup>a2</sup>
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<sub>b3</sub>

February 16, 2021 at 3:38 pm #31154UshaTParticipant
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