How to Calculate Faster than a Calculator - Mental Maths #2| Addition and Subtraction

till the end of this video you will be able to add and subtract numbers in your head faster than you could ever imagine so let's begin [Music] hello geniuses welcome to the second part of method genius mental match series in this video we will learn how to add and subtract numbers lightning fast so i have a question for you add 759 and 496 in your head right now and not that time okay so this is how most people would do it they will imagine 759 and 496 then they will add 9 and 6 and then they will take the carry and so on basically they will go from right to left and this is basically what we learn in school but what if i tell you this is the worst way to do it if you are doing it mentally on paper it is fine but for mental maths this is the worst way because see how do we read numbers from left to right and in here we are going from right to left so this is the exact opposite that our brain is trained to do so this is not the right way of doing it so how do fast mental mathematicians do it they basically go from left to right and also this method has a really good advantage that as we are computing our answer we can just say it for example if you have computed the first digit in here you can just say it and this will give the illusion that you are faster than a calculator because in the previous method we compute the last digit first and we can't just say it but in this method we can just say it and give a faster than calculator illusion so this is how to add 759 and 496 monkey instead of adding 496 add 400 first so 759 plus 400 is 11.59 now add 90 so 1159 plus 90 is 1249 now in here 12 is our final answer so we can just say it 12. now people will think that we have computed the whole answer but we need 49 plus 6 which is 55 so 12 55 is our final answer now before getting the final answer you have said 12 so people would think that we have calculated faster than a person with a calculator so this is how mental mathematician give the illusion that they are faster than a calculator while calculating their answer now the main principle of this left to right method is that we basically convert hard problems which our mind can't solve to simpler doable problems and as we compute our answer the problem becomes easier and easier and this is why this method is used for mental addition subtraction also for multiplication and division so always remember that every fast mental mathematician always go from left to right they never go from right to left so in left to right method we need to convert hard problems into simpler doable problems so see that same problem 759 plus 496 can be done in a more simpler way see 759 plus 496. instead of adding 496 let's add 500 so 759 plus 500 which is 1259 now in here we have added four more so let's subtract four so 1259 minus 4 is 1255 which is our answer so this is how fast we can do it if we are more creative so rule number two of this left to right method is that always be creative the more creative you are the more you will give the illusion that you are faster than a calculator because see in here we just computed 12 in the first second so we can just say it so in here we are faster than a person with a calculator now try 92 plus 53 so 92 plus 50 which is 142 plus 3 is 145. now you can say 140 before you have calculated your final answer now try this one 92 plus 59 now if you added 60 first then you are on the right track so 92 plus 60 is 152 now we have added one more so 151 is our answer so this is how fast we can do it now as i always say the more you will practice the better you will be in mental maths so that's why i've created this free game known as math blob run in this game there is a bad blob who is chasing a good blob who wants to eat it and solving mental math questions can save your blob so this game will help you to practice mental maths in a fun way download link of this game is in the description of this video i also added online leaderboards in this game so that you can compare your high score with others and also compete to get the number one spot now let's see how to do mental subtraction same principle here always go from left to right convert hard problems into simpler problems and be creative so try this one 76 minus 25 so now see 76 minus 20 is 56 minus 5 is 51 that is our answer now if you are creative you can do this problem without even doing subtraction see 25 3's are is 75 and 25 is 50 and 76 is one greater than 75 so 51 is our answer now see with creativity and practice you can be faster than any person with the calculator because they would be just chunking the numbers and you will just say the answer now let's try 66 minus 39 now instead of subtracting 39 subtract 40 so 66 minus 40 is 26. now we have subtracted one more so add one so 27 is our answer so this is how fast you can do it and also say 20 before computing that 7 because this will give the illusion that you are faster than a calculator now try your mind on 857 minus 298 now subtract 300 first so 857 minus 300 which is 557 now add to 557 plus 2 is 559 that is our answer and 550 can be said before computing the last digit and with that you will be faster than a calculator now i have a cool bonus for you which is known as compliments this will help you to even be more creative this method is used to compute how far is the two digit number from 100 so see how far is 38 from 100 or in other words how much is 100 minus 38 so instead of doing the subtraction look at this how far is 3 from 9 6 and how far is 8 from 10 2 so 62 is the complement of 38 which is 100 minus 38 is 62. now let's see how compliments helps us to calculate faster so see this 536 minus 378. now if you use the left to right method you can do this 536 minus 300 then 70 and then eight but this one is a little longer so what you can do is this subtract 400 from 536 which is 136. now the complement of 78 is 22 so 136 plus 22 is 158 so this is how compliments help us to calculate faster now with this and some practice in math lobe run you will be able to do any subtraction and addition problem lightning fast also most of the tricks that i taught you are from this book secrets to mental math which is a really great book buying link of this book is in the description of this video and also thanks for watching this video and always remember that math is everything you

Channel: mathOgenius

Views: 2,437,578

Keywords: how to calculate faster, how to do lightning fast calculations in a snap, How to Calculate Faster than a Calculator - Mental Maths #1

Id: Hs0wjbxvCt0

Length: 7min 59sec (479 seconds)

Published: Mon Nov 16 2020