so good evening uh any doubts in addition i I know no doubts at all that was the easiest topic yes any doubts any questions you have in addition what happened no no sir it's clear sir okay yes sir so we'll be starting with subtraction today and we'll be finishing also so what do you mean by subtraction first question subtraction sorry taken away what do we mean by subtraction just AC on yes what do we mean by subtraction yes arish ta aruna anyone sorry decreasing the values decreasing the values okay so why you're not confident sir basic questions these basics are required because when students will come they don't know now sir yeah tell me one value from other so how will you define how will you say yes aruna tuna in addition in addition we will add the two values three values but in subtraction we will only do one value only one value to one value what we'll do one value to one value that means uh we have to do in one time only in addition yeah if suppose uh please you are not mentioning a word what you'll do we'll do one value one value what is that that is what I'm asking you yes kalyani you're smiling so tell me no no no sir I'm not smiling difference I think difference with two into numbers difference uh the the process of finding the net difference between two numbers that's all two numbers that's all see ultimately when you start a topic you have to ask now students do they know or not all right so a minus b is equal to c now this is a general concept what is a called what is b called what is c called anyone my new hand that is not correct and third I don't remember sir now that is itself is I think yes harish pushpa always hiding why you should ask What if subtraction is a process of finding net difference what will be A here B and C called as difference all would be called difference who is this 1 + CPH hello okay so we call A as minute b is called as subtraen from what we subtract that is called as subtraen and see of course the net difference got it so this is the basic what happened harish not able to do any difficulty coming okay now there is no problem at all if minute is bigger if m is greater than s there is no problem at all let me give you a examples 47 - 25 7 - 5 possible we can easily do 2 4 - 2 very easy we can do two so that means m was bigger in both the steps both the place values at unit position also at 10 position also and s was smaller so there is no doubt at all no problem at all we face but the problem we is when subtraand is bigger [Music] now here 7 and 8 when you compare these 8 is bigger than seven right bigger than seven means we cannot directly subtract 7 minus 8 not possible so what we do we take a borrow this is subtracted by one and this is increased by 10 which is always a confusion for students okay why it decreases by one and why it increases by 10 but anyhow 17 minus then 8 we do and we add 9 and 3 - 2 we do one but so this is where confusion lies the borrow and when we started with Vic maths I told you the first thing we will not have borrow in subtraction there there are two silly mistakes considered the first silly mistake is your multiple carryovers and the second is now multiple carryovers generally you get in addition multiplication borrow you get in subtraction you'll be getting in division so you saw that since we were doing on the basis of balancing line our carryovers were I won't say they were decree uh they were removed but yes they were diminished or they were decreased to some extent they were reduced but in case of borrow we don't have borrow there is no borrow system in Vic maths so How to do i'll take the same question again 47 and what I took 28 28 now this is your man this is your subtra whenever s is bigger what we'll do is we will find the complement of the subtraand so what is the complement of it we did one exercise two sir two sir so we'll write two over here and the moment we are writing complement we are adding one sudha sign to the next line correct now we will not subtract rather we will multiply minute with sorry we will add uh your minute with the complement of the subtra so these get added 7 + 2 becomes 9 and 4 minus 3 becomes 1 so no carry no borrow is there did you understand this thing yes sir one more example uh you can write down all these words because this once you have to write Huh yes sir again 92 - 35 so again we cannot subtract so let's take the complement five complement is again five now see the magic you cannot subtract two from five but you are taking five and adding now so 7 and 9 - 5 becomes four if you want to check go ahead digit sumus 57 sirus 57 digit sum is two all are attending the class today what is the digit sum of 35 that is eight what happened Harish so digit sum of 92 is 2 digit sum of 35 is 8 so what is 2 - 8 it is - 6 and remember when we were doing digit sum whenever digit sum is negative add 9 so that means three and here also if you see 12 means three correct see I know you are not doing digit sum again and again but please remember when you are teaching it to class third fourth fifth or any ask them to do digit sum at least for first 10 20 days then only they'll remember that they have to use this and you'll be benefited because it is the internal confidence that will keep them going if they lose confidence they'll not continue with the classes so you have to maintain that confidence in them and that will come only with digits right we'll try two three simple questions and then we'll finish it up 931 542 again one cannot be subtracted so 8 8 and 1 9 five cannot be subtracted but five can be added 3 and 5 8 and 9 - 6 clear yes sir very good uh first one is from 10 and second one is again from 9 but four friend is uh four compliment is five from nour compliment from n four compliment five compliment one compliment so from 10 it's nusion okay sir I I have never taught that point because there is a reason behind it i'll tell you two compliment eight three seven so when we when we talk about compliment means by only 10 see nine if you'll remember then you'll you have to remember two things and then what will you do in double digit numbers so I I'll never go for that concept of complement of nine okay what similarly what will you say for 11 then 89 and if it is a complement of nine what will you say what is the answer it's one sir 11 yes it is 89 complement of 10 complement of N how will you find that then ch don't be confused so we are simply we are finding the complement that is 10 one only and we'll be considering that complement only everywhere this is again five so we take the complement five this is 9 - 6 so 3 correct yes okay one more 900 - 542 give me 315 correct yes others do see you know you are don't I know you know the answers immediately you can answer but take it practice with this method because with bigger numbers letters I'm doing good good because I know now your your addition and subtraction is very fast it's compliment only sir I'm M okay good yes everybody got it harishna yes very good 8 3 6 5 6 4 - 5 6 7 8 So again nothing eight means two two six correct Eight means here also two seven means three so 3 and 3 six 2 6 8 6 correct yes okay let practice three four questions and then we'll Yes any doubt bhan no sir no did you get the reply from her she uses tab you asked her yes sir she She's using tab yes I understand i think it's Lenovo tab or something sir it's 189 okay yes harish what happened harish are you not able to do no don't after the class don't say me sir please repeat everything sir sir 789 sir sir sir sir this one please explain one 83 64 967 last digit how can which one s you are saying about this 8 - 6 or which which are you calling as last left side or right side left side sir The left side we were having five correct and one huh which one you said left yeah five five so five and five correct so 8 - 6 is can you subtract 8 see please understand one simple thing if the number given is 97 minus 34 now there where will you apply compliment because it is directly yes sir compliment will be applied only if you have a trouble in solving now if your M is big already bigger than S there is no issue you'll take medicine if you'll take medicine only if you are ill no or you'll take medicine without that so that is the thing correct yes okay so now if you are uh I didn't mention you the name so see here we are taking sudha sign so this is called as sudha method of making subtraction right this is the first method we follow second we'll do today that is called as vinculum subtraction it will be more easy than this also but it is only for those students who have done vular numbers correct so I'll teach you and then we'll go for simultaneous addition and subtraction one more subtraction uh is there i think I have okay you you got the new books so you you have that also you know earlier book it was not in the book one it was in book four so okay so right now we are doing shudha 8 765 2 4 58 do it now see it will be very simple subtraction yes okay this is very easy because there is only one big digit so two shoddha so 0 7 3 6 finish correct yes sir aruna is it clear yes sir aruna yes sir sure good good good 38 07 38 07 okay 9 1 2 3 5 7 5 4 3369 okay very good very easy topic right 6 1 0 1 6 2 7 8 9 6 3 1 2 0 33 1 2 0 okay last 67 any doubt any question here any questions yes tuna aruna no sir alani pushpa any questions you have no sir okay now the ne second method is more simple and see here now your understanding of vinculum will come into because if you have that understanding you'll be able to answer within seconds i'll give you a very small example first and then it was first question was 47 - 28 correct and at that time we were not able to subtract 8 from 7 here can I subtract 8 from seven yes I can write one are finish this is your answer now verbally if you are strong if you know the rules or even if you can evaluate it is nothing but 20 minus 1 so 19 so making the use of finulum got it yes one more one more so see how simple it is Instead of understanding that carry over so 2 - 5 rebath 9 - 3 6 60 - 3 57 finish now you apply your rules or you apply expansion format whatever is there the more it will become easy and easy got it any doubt no see within Half an hour you have completed two topics on subtraction so such easy things are 931 - 542 do it with vinum first tell me the vinum answer so four one bar one bar yes sir 389 sir so this will be four one bar one bar that means 400 minus see what happens when you are doing this mentally your speed is increasing you are learning how to answer fast right and even mentally calculations small calculation the students are able to do fast so 38 9 same questions in these two exercises I have put the same questions so that one should Understand that how that was solved earlier and how now 358 sir 358 sir okay 81 18771 we just did this question 6347 Mr frames 793 3 627 it's 556 146 okay 874 579 29 clear any okay 72 65 - 3 4 58 3807 yes sir sure yes sir 912 35754 double three six minds james any now any doubt anything any topic you feel key yes this is not understood or anything you have left with if how many numbers sir we can do that much only if it is here now we had given you four if it is six seven means same so there is no problem at all now let's Anything answer would be coming let's say some answer comes 1 2 bar three bar four bar four five or something you know how to convert we did vulum numbers yes immediately you'll be able to convert no either you use your concept see positive keep above if it is first digit is positive and negative down so zero finish that's why we teach rules now now one more topic is there which is very important because that is the base of all money transactions across the globe but before this let me ask you one question i asked you i I remember but now we'll have the solution so how do we calculate if we are given a set of numbers where two are positive two are negative 23 + 24 okay - 35 - 8 so that means a you are doing this and second you are doing this and then you'll do a minus b so step three steps you will be following correct yes sir i want you to do simultaneously is it possible in maths yes is it possible who won that is what you told us all from i I just asked is it possible in maths now see if just just think about it such simple thing is there that we have four numbers but I cannot add and subtract simultaneously so how limited is the you know knowledge of mathematics or you can say the way to solve the things they are just cramming the concepts if you ask this question to any scholar he'll answer the same thing add positive subtract negative because this is what they have been taught and the second reason is because in mathematics we consider the number as a whole there there is no value of separate digits but here it is there so very simply if I take 83 this is minus 35 can I write it as three bar 5 bar 24 as positive 5 bar 2 bar finish and add everything now by chance this five and two minus 7 and this + 7 all go off Eight eight go off so only 20 is left so the chances of errors are reduced why because you're doing one step see the more calculations you are doing there are more chances of errors that was step one a was adding the positive step B was adding the negative numbers step three was subtracting each other and let's say in case B was bigger then there would have been another confusion the answer would be negative or positive but here you are doing everything in a single step this is called as simultaneous addition and subtraction but here you have to be one one thing has to be very uh uh you should know that in case of addition you can follow place-wise method you can adopt sudha method for addition but for subtraction only vinculum you cannot have sudha method of subtraction so until unless vulum is there you cannot have simultaneous addition and subtraction so this is the value of vulum numbers did you understand please write down this example then we'll practice 3 4 Done so 117 117 or only 17 117 how is it possible okay yes so 63 bar is it right 57 sir 63 bar is correct but what is 63 bar 57 yes go on what happened i will check h you're down today what happened all fine seven correct yes sir 57 okay six digits I have given this time the whole one is only one six sorry i mean 289 - 670 + 168 + 3900 - 200 + 188 yes sir 174 174 Wonder if [Music] there is some emergency see I have to go but I'll just explain this somebody is in hospital i just have to rush yes this is I will do this explanation if you're okay with it no I I'll tell 289 six bar 7 bar 0 correct [Music] now positive is 1 68 again this is positive so 3 9 - 200 so 2 bar 0 0 and + 8 on zero you need not to write now just see all are positive 9 8 17 17 and 17 34 so I'll use suda method place wise method of addition here so that it becomes easy here 8 - 7 1 1 and 6 7 7 and 9 16 and 8 24 correct okay now here I can cancel this and this very easily and positive are 1 2 3 so one bar up till here Any doubt no sir okay so four three goes here it becomes seven two goes here now this is negative so that means one and two positive so one clear yes uh sorry I have to leave yes huh yeah tell me tell me tell me which part so last one explain one second sir last lines one bar last this is one bar no so what do you do if it if it was one what will you do 1 + 2 3 you make no no sir so if it is negative what will you do let's say this is minus this is + two how will you do mr 2 - 1 one see you just have to see this uh sign got it yes okay i'm sorry but uh I have to some emergencies there right and you can complete this exercise this will be done rest I'll take right thank you sir okay sir thank you sorry good night sir