Adding & Subtracting Mentally in Single Line II No More Errors II No Calculator Trick

[00:00:02]Hello friends. Welcome to Suresh Agarwal's mathematics shortcuts. One stop for learning the smart tricks which are required to excel in all sorts of competitions, specially when you are at school level and you are trying to excel in various Olympiads, you know, the NTSE, the Aryabhata Ganit Challenge and SOF Olympiads, you know, and trying to be one among those top 1% students who crack these Olympiads, the channel is for you. And we strive to provide you some very very important tricks through which you can look better, you can look exclusive. So friends, what do we have in this video? A very basic thing, but a very important thing. Mental addition and subtraction of big numbers. That's what I am going to take up for this particular video. Adding and subtracting big numbers and I tell you when you have four or five numbers separated by plus or minus sign, most of the students are doing the traditional thing, writing one below the other, adding, subtracting and doing all sorts of steps. What if I tell you that if five numbers are given to you with a plus or a minus sign, you can actually find the result in a single line?

[00:01:13]Oh, that sounds interesting, right? And so to learn that, you need to watch the complete video.

[00:01:21]This trick which I'm telling you is a part of our ultimate guide to speed maths which is a must for excelling in the competitive exams and developing those tendencies which are required to crack the exams in the first attempt.

[00:01:37]So friends, first let me tell you the trick and after that I'll tell you how to get a copy of that ultimate guide to speed maths, an exclusive content containing book.

[00:01:48]Friends, suppose uh we have a question having uh three-digit numbers and two-digit numbers first, okay? Uh after that I'll go to four-digit numbers also. Right?

[00:01:58]Let's see how we can do that in a single line. Now, suppose the question is 978 - 84 + 263 - 615.

[00:02:11]Now, I know if if you know your mathematic mathematic mathematics well, but you know, you always struggle in the speed part, then you will think, "Oh, that's easy. 978 - 84, whatever you get, + 263, and whatever you get, - 615." Oh my god, that's huge, you know, and chances of errors are so much in doing that because you are doing it in four or five steps.

[00:02:38]Let's try it in the in a single step, okay?

[00:02:42]Now, see.

[00:02:43]First thing is, let me count the number of digits in each number. Here, we have three digits, two digits, three digits, three digits. So, the highest is three digits. So, I'll rewrite this as this 84 will be written as 084. Although, you don't need this step, but I'm telling you just because, you know, we should know the basics first, and then we should apply the basics to get the answer. So, this is not required. You can do it from here also, but just to avoid confusion, I've written it here.

[00:03:14]Now, instead of doing the complete numbers, let us go by the place value.

[00:03:18]That means the hundreds places. I am just thinking that we have the hundred places only, okay? And we have to add and subtract them according to the sign given here. So, 9 - 0 is 9, 9 + 2 11, 11 - 6 is 5.

[00:03:37]7, now I'm coming to the tens place. 7 8 is -1, -1 + 6 is 5, 5 - 1 4.

[00:03:48]And then, 8, the unit place, - 4. 8 - 4 is 4, 4 plus three, seven. Seven minus five, two. Oh my god, we have the answer, 542.

[00:04:02]Now, you must be surprised, you know.

[00:04:05]This this will not happen every time.

[00:04:08]Sometimes you will get two-digit numbers here, and sometimes you might get a negative number here. And I'll take all those examples also, okay? This was easy, right? Let's take one more easy example, and then we will go to some difficult ones also.

[00:04:23]So, suppose you have 297 minus 132 minus 646 plus 89 and then plus maybe 708.

[00:04:36]Hmm, two negative numbers and three positive numbers.

[00:04:39]Three-digit, three-digit, three-digit, two-digit, and three digits. So, let's start. Let's equate the number of digits. I'm writing this step, although I don't want to, but it's okay. Just to avoid confusion, I'll write 89 as 089 and plus 708.

[00:04:58]Start. Two minus one is one. One minus six is minus five. Minus five, so this doesn't matter. Minus five plus seven is two. So, we have a two.

[00:05:11]Nine minus three is six. Six minus four is two.

[00:05:16]Two plus eight is 10.

[00:05:20]And plus zero is 10 only. So, we have a 10 here. So, I'll put a slash now because I have one more step now.

[00:05:27]Seven minus two is five. Five minus six is minus one. Minus one plus nine is eight. Eight plus eight is 16. Oh, that's a two-digit number again, 16.

[00:05:39]So, the two-digit numbers also don't scare me. Why? Because retain the unit digit, carry forward the tens digit. 10 + 1 is 11, 1 1 carry, and 2 + 1 is 3.

[00:05:50]316 is your answer for the question.

[00:05:56]Friends, these are not difficult things, you know, these are things which you need to pay attention to, and if you pay attention for 1 hour also, your calculation speed will be very very amazing. And talking about calculation speed, this is what I always tell you, investing in good quality education is really important. You can't You don't become a genius, you know, just by watching people do calculations on board and on YouTube. You need to do it yourself. And to do yourself, you should have good quality content with you. So, if you are a parent, if you are a teacher teaching mathematics, a tutor, an organization, an institution, educational institution, taking tuitions at home, you know, these are the books which you have to present in front of your students. And that's where, you know, you are actually doing justice with the students. It is not about teaching questions, telling them, "Okay, this is the formula, and these are the five questions."

[00:06:50]That That can be done by anyone, right? But, giving quality content is really important, and utilizing the efforts of people who have worked in this field of speed maths is really important. So, this is the ultimate guide to speed maths volume 1 and volume 2.

[00:07:09]A reservoir of tricks which are exclusive, and which the educational institutions, you know, they will teach in lakhs when you are preparing for maybe some university entrance exams, you know, they'll charge you in lakhs. And what How When I say the two volumes, they cost less than 1,000 rupees along with the shipping charges, you know, people are like, "Oh my god, 1,000 rupees?" And that's [clears throat] where the problem is.

[00:07:36]Good quality content, you know, you got to be ready to invest little bit on your education. So, this contains video links also, 3,700 practice questions, and this is like a must for all the school students also.

[00:07:50]So, if you are a college school owner, you know, who a director of a school or owner of a school, give your children these good things right from the basic level so that, you know, your school also gains a unique name in society for having done something useful for the children and not just telling them, you know, this is written in the book, right? So, friends, how do you get a copy of this speed maths combo?

[00:08:15]You can send me a message on WhatsApp 9896369963.

[00:08:18]This is the WhatsApp number. Or the Amazon links are also given in the description of this video. So, you can purchase directly from there also.

[00:08:26]Right, friends. I'll take some more questions.

[00:08:29]Adding big numbers, that's what we are up to, right?

[00:08:32]Let's talk about four-digit numbers.

[00:08:35]4638 - 1924 + a three-digit number, 863.

[00:08:43]Now, what do you do with this?

[00:08:44]Quite easy, you know. First thing is to equalize the number of digits. 4638 - 1924 + 0863, right?

[00:08:56]Now, go place wise. 4 - 1 3 3 + 0 is 3.

[00:09:01]6 - 9 is -3 -3 + 8 is 5.

[00:09:06]And then we have 3 - 2 is 1 1 + 6 is 7.

[00:09:11]8 - 4 is 4 4 + 3 is 7. Look at this. No double digits, no negative numbers, and you get your answer. Now, I'll tell you one important technical point here.

[00:09:22]Suppose, after having done all the places, you get some numbers, right? And you get numbers like 3 -2 7 and a -1. Suppose, okay?

[00:09:35]Now, what do you do with the negative numbers? This will complete the trick.

[00:09:38]Borrow one from here and subtract this from 10.

[00:09:43]Borrow one from here, subtract this from 10, and you will have some more numbers.

[00:09:47]10 minus 1 9. 7 becomes 6 because it gave away one. 10 minus 2 is 8, and 3 becomes 2 because it gave away one. Now, this is what you need to do when you have negative numbers. And when you have double digits, retain the unit digit and carry forward the tens digit. Now, this is what you need to do, and uh you know, practice is a must. Practicing 40-50 such questions and very important for banking exams.

[00:10:13]You know, banking and railways exams, you get such a huge lot of questions in which addition and subtraction skills are tested. They'll give you 40 questions, and they'll ask you to do it in 20 minutes, you know. And you got to be really really sharp handling those numbers on your fingers. So, friends, very important video for all the aspirants. Very very important that you catch hold of a book uh which actually gives you 350 such short methods, the ultimate guide to speed maths. Uh find the Amazon links here in the description of this video, and let me know in the comments below is this trick working for you. All the best.