Fast Math Tricks - How to multiply 2 digit numbers up to 100 - the fast way!
Vložit
- čas přidán 25. 11. 2011
- How to multiply 2 digit numbers numbers up to 100 - calculating the fast way!
Using this method you will be able to multiply any pair of two digit numbers with each other - faster than a calculator! Become a math genius in no time at all using vedic math!
To see how to multiply 2 and 3 digits using a variation of this trick follow this link: • Fast Math Tricks - mul...
To donate to the tecmath channel:paypal.me/tecmath
To support tecmath on Patreon: / tecmath
To buy tecmath mechandise: teespring.com/stores/tecmath-...
To anyone wondering what to do if your second set of numbers comes out in double digits, you put the left number in the blank space. Then you finish like normal simply adding that number and the one that would usually be in its place, and simply carrying the extra if those number come out over 9.
Example:
12 x 15
1x1=1 and 2x5=10
So that’ll look like
110
Then 1x5 + 2x1 = 7
Now we take that 7 and add it to the 1 in the middle position and there’s our answer: 180
And to do big number you can just combine that with what he says in the video.
Example:
79x88
7x8=56 and 9x8= 72
So we have 5672
Then of course
7x8=56 and 9x8=72
56+72=128
We then take that and combine it with our previous number
128
5672
Add that how it’s lined up there and you get
6952, and that’s our answer
Hopefully this helps someone!
I dont understand why this guy didnt explain this. Helped a lot
How do you combine 128 and 5672?
@@sozukuKrtzLNK he first add the 67 and 28 then the remaining 1 is add to 5 which makes it 6 95 2
THANK YOU FOR THIS. Not quite the way the video explains it. I was multiplying 29 × 47 and the video method wasn't working. This method works. Thanks!
Yes!! Thank you! I literally just asked this question … then saw your post. 😆 Thank you!
Some times he just sounds like he is gonna burst into laughter😂
bruh I just graduated highschool and I'm only learning this now lmfao
Same
Hahhahahaha same bro
LOL
bro im a sophomore in college and just learned this
Studying for my GED 😔
I'm 38 years old and not very good at math. I blame myself out of anyone for this. I've watched a few of your videos so far and have learned more in regards to math than the past 36 years of my education. You are making math fun for me. The only thing that is holding me back now is mental math and doing these in my head. I'm working on that though. Thank you!
Born and raised in the United States 🇺🇸 i love my country. But im 56 and now learning a way better a quicker way from you has left me like WTF! When it comes to our educational system. And very grateful and appreciative to you sir. Thank you very much
@Otto von Bismarck not funny, try again
good all you need to know is that the earth is flat
Right but as long as you have scratch paper is all that matters we all put our jeans on,one leg at a time .. if you can do it with no calculator you are the bomb..lol
School system was always nothing in the first place
I hope its not too late to post a comment,
sir, you cant imagine how far your lessons are reaching and how many minds are they changing , just for you.
thank you, from the bottom of my heart.
same
Agree I am an accountant an learning this now. 🙏🏽
@@apriltwenty4945 Do you like accounting?
Thank you from Florida
I agree
I am in school and the kids in my class look at me like i was from a diffrent planet when i said the answers correctly over and over again.
+Jtheviper Cool!
Jtheviper me to
Jtheviper my teacher called me to go and solve the question at the white board and the class looked at me like "ugh it's this bitches turn" (litter ly) you guys get that pun?(it's pretty bad what am I doing XD)
Turbulent
Is to fast ta simple multiplication nal hi ho janda hai
Are the math lessons from 2011 helping?
“Yes”
MiguelGaming ReadyChannel lol
Wow this was made in the year i was 1 and i am 9 right now wowwww this is old and yes it helps🙂
i keep getting that AD
Ulol
Some of the lessons still helping from 2000 B.C.
Oooohhh, this is FOIL method (First, Outer, Inner, Last). I did not realize that cause you explained it so well, and made it look so easy. Thank you for this sir!
This man has taught me more than my school
🤣🤣 same I'm like wtf was my teachers even teaching me
Same
Me too. Love your profile pic.
Me too😂
seriously?? last time im in school was 4 years ago now im 17 and im suprised
Where the heck were you when I was in high school... I’ve watched 4 of your videos and I see teachers don’t teach these because once you get it... you don’t need anything else... you just became amazing.
Dude why tf doesn’t my school teach this 😭😂
Because they want you to struggle and get headaches.
@@bustergundo516 ikr
I don't know what you have learned in school to solve this - but I have learned a way which is equally fast and which you can easily transfer to numbers with 3 or more digits...
By the way: doesn't everybody use a calculator to solve this?
@@chglubb booo
@@chglubb well you have a nice school ig cause almost every school doesent teach this
I got 704
3213
and 4182 in less than 2 minutes and I solved them mentally....☺️
Thanks a lot for this method 😄
I was expecting this to be super complicated, but after watching 5 minutes of this video, I could solve each problem in around 10-15 seconds. I'm super happy right now.
cool
Bruh I solve it in 5 seconds using normal method
@@AIBuoy134 Good for you, but this is for people who can’t mentally calculate fast
I learnt this in Primary School and the teacher called it the “ Rainbow “ method. ( P.s. you do the best math videos )
Ok.
Lol me too 😂
No one ever taught me this in school. Love your videos.
@@carolynroberson8407 I wish I knew this. I was terrible at math. lol
Nope he is the worst teacher
I suffer from maths dyslexia and anything to do with maths make me come out in a sweat . You sir are a great teacher , love these maths tutorials. Thank you so much . I’ve subscribed
I used to leave my math exam paper blank. I could not understand a thing.
@@djamilac9556 lol
Why are we not teaching this in school?! Ive now gone from not knowing my times tables to multiplying double numbers! Awesome thanks!
Tecmath,
I am a viewer and I love your math videos! One thing I hate though, is how you never explain it. Other kids at my school ask " Wow, you're good! How do you do the strategy?". I tell them the strategy. BUT, they wanna know WHY IT WORKS! So please explain why it works if it is less than somewhere around 10 minutes to explain. PLEASE like this so he can SEE IT!
- A Student In Math
If you want to multiply two numbers between 9 and 100 with this method you have to know that what means if the number is on the first or the second place (and etc.) in the ten numerical systems.
For example:
12 X 34 equal / can be written as (10 x 1 + 2) X (10x3 + 4),
or generally (10a + b) X (10c + d).
Let us multiply these numbers: (10 x 1 + 2) X (10x3 + 4)
it will be (10x1X10x3)+(10x1X4)+(2X10x3)+(2X4),
or generally (10a + b) X (10c + d) = 10aX10c + ( bX10c + 10aXd) + bd.
…. as _X 100 + _X 10 + ... _X 1
The result has a part as 100's from the 10aX10c, has two parts as 10's from the bX10c plus the 10aXd (as sum of cross-multiples) and has one as 1's from the bXd values.
The result will be 3 or 4 digits only.
I hope that this helps.
It makes use of basic algebra if a x b = c is the question and a and b are any 2 digit numbers. Then a = the sum of it's parts eg 10s + 1s.
Eg if a = 25 it is the same as (20+5)
In algebra if (d+e)×(f+g) = df+ef+eg+ef
Eg 24×53 = (20+4)×(50+3)
=20×50 + 4×50 + 3×20 + 4×3
Notice 20×50 is the first part you put down ie the biggest number. 1000. But in order to make addition easier you leave the last 2 units blank therefore 10_ _. Add in the units 3x4=12. And you get 1012. But you still need to add 20x3 and 50x4=60 and 200 or 260. Lose the zero and you have 26_. Line them up.
10_ _
26_
12
1272.
That's what you do to prove it. But you take shortcuts in your head to get to the answer. Condensing and compressing it to be easy to understand.
Hi!, I know it's a late response but anyway. The reason it works its because it's an application of the distributive law. So for example 22x32 it's the same as (20+2) x (30+2). He is using it out in a summarized way.
Bro what about 46 into 59
@@Doc_Bavarius Not sure if you can edit your otherwise excellent comment but I think you'll find (d+e)×(f+g) = df+ef+dg+eg
this video is really really helpful this time i got 99.7 in maths because of my fast multiplication compared to last time when i got 80.5
+Pratima Mehta Congrats!
Interesting but how do you get a 97.7?
+ZingZang Oliver I had a 103% called extra credit and paying attention
+Doom Patato Oh, i was just a little confused because in my school we dont do extra credit.
How did u get a 99.7? My teacher saids it's impossible to get a 99
Brilliantly and clearly said, additional points for brevity. Great video.
This helps me a lot now I can spend less time trying to figure it out.
@Adib Farhan 480000
chiaroschurros it’s index, not multiplication. multiplication sign is *
Your just an amazing teacher who inspires confidence and makes learning maths FUN!
Love this guy he's getting me work up about math again
I love these videos. Thank you for sharing how to do seemingly complicated sums, easily.
THE QUESTION REMAINS, WHY WERE WE NEVER TAUGHT (AND STILL NOT TAUGHT) TO DO MATHS THIS WAY IN SCHOOL?
I’ve always had a really good memory in mind for math but this would’ve made me look pretty incredible if I had mastered more of these as a kid, I need some shortcuts but there’s so many do you can learn it’s pretty cool! Never too old to learn.
Thanks for the tutorial mate! This helps a lot!
You, solely, are going to get me passed my ITT Professional Numeracy Skills test! For that, I thank you!!!!
So did you passed?
You're a great instructor. Thanks!
This is what my 3rd grade teacher took 1 year to teach and you taught me in 6 min 26 seconds, bravo
thank you so much. I have learned everything for your video the system of the math.
I love this video very much!!!,
You have made multiplication simple to me!!! THANK YOU :)
Thanks so much for this video. I have been wondering how to do these questions and now I know!
Amazing! Just amazing mate! I didn't know there was a trick for this! Cheers!
You sounded so excited solving the third math problem 😂 Even I started to get excited and I don't even know why, I hate math 😂
I would have failed grades without the internet THANK YOU!
Never heard of this 😱 luv this!
Thanks brother for helping in such an easy and interesting way , it really made me tension free for my child's math multiplication problems that he has to solve without working, thanks again👍
L+ratio+thumbs+nothumbs+nomilk+toomuchbananas+Quadraticformula+bingbong+bin7gchilling+bing
😊😊
This is Amazing! Thank You Very Much!
If you got 4 digits after the two first calculations, the use of the "_" must be avoided. e.g. 75x64
7x6=42 and 5x4=20, then you got 4220.
(7x4)+(5X6)=58
4220
58
4800
Jose' Gonzalez, thank you for explaining. I am coping your answer to the people who have disagrees.
You mean if you have 2 digits from the products of the ones places
For example: 25x25
2x2=4 and 5x5=25 We have 2 digits in this product so don't use the _
425
(2x5)+(5x2)=20
425
20
625
The answer is 625. If you used the _ it would look like this
2x2=4 and 5x5=25
4_25
(2x5)+(5x2)=20
4_25
20
6025
There would be an extra digit which we don't want.
@@mariafe7050 how would you solve 57 x 17?
@@Theismadsen. I figured it out if you get a double number on the last part of the number use that first digit to add to the middle.
I just got a job that involves a LOT of mental multiplication and your videos are saving my LIFE! THANK YOU! :D :D
Which job requires mental multiplication a lot
Thanks for these tricks tecmath!
Thank you for helping me refreshing my math skills. I greatly appreciate it. Sure wish I had a math teacher like you growing up. Chances are I wouldn't have despised math as much. Thanks again!
bing bong
Lol
TecMath this is awesome!!!!! I'm feeling like a genius! And I can listen to your accent all day! This is exciting
What happens when the units part of the answer is 10 or over? Lets say it’s 12 . Do you write down 2 in the units and then add the 1 to the tens column?
@@bambispoon4305 what?
Thank you for the video. I was doing this and realized that it is faster to do the equation backwards. Starting from the right side of the equation.
You are so helpful because I don’t no how to do the column method for 2 digit by 2 digits so that’s really helped me out. Thanks😃
Awesome !!! you've made calculation become easier now thanks alot :)
This was so helpfull for me! Thank you so much for this teach! I'm not great at calculating... usually i calculate with the phone, but that is very good! Big like for you! 😊
I love your topic sir. Thank you for sharing your knowledge to us. 🙂
You... good sir... have earned a subscriber and a LOT of likes because I’m probably might watch all you’re videos since there really helpful
YOU HELPED ME DO MY HOMEWORK BECAUSE WHAT THEY DO IS SOME COMPLICATED CARYING OVER like 10 times
u saved my time
I liked and subbed
The reverse FOIL process, that's genius!
Just one thing. The results of the second numbers being multiplied are single integers. I have practices where the product of the second numbers are two integers. I found that if you add the first digit of the product from the second integers to the sum of the products from the first and second integers (consecutively) it's correct.
Well, taking 26 x 86 as an example, the first stage of the calculation, (6 x 6) yields a result of 36. So, instead of a '_6' as shown in this video, you would have a '36' there instead. The next stage, (2 x 8) yields '16' giving us an intermediate result of '1636', right? In stage 3, ((2 x 6) + (6 x 8)) yields a value of '60; add that into the '1636' as demonstrated in this video and you are left with '2236' and the correct answer. :)
@@undercoveragent9889 try 94 x 36. It gives a wrong answer
@@twesiimemaurice8846 yea this track doesn’t work there’s actually a lot of answers that don’t work with the equation.
How is it wrong?
Thank you for posting this video, totally awesome! 😁🤘
40% of the comments are wise guys trying to prove this method wrong because they don't know how to use it properly.
ya u r right
ikr
the
the yu y6
6
I'm a banking student it is really helpful
I am happy to know this easy method Sir.....☺️ Thanks so much for the tutorial 🙏
This is absolutely the most helpful thing ive seen being in highschool.
I swear this men sounds like he has so much confidence in me, and i don't even know him.
9
"Big brain time"
"it's" BIG BRAIN time
Finallyyy i got the reallllll math teacher that actually helping students but not shouting at them for not doing correctly. School teachers should watch these vdo so that they could teach students this wayyyy...
I learnt this right in time yayy. Thank you so much sir, I really like your teaching style...
Wish I’d have had you as my maths teacher when I was at school
+Tecmath, thanks for the multiplication method
It really helped me,
I really appreciate this method
Thank you so much
A very useful video Tecmath. Thanks so much.
omg, all my life ive been using the long way. BUT THANK YOU FOR THIS
If anyone else is wondering:
For values like 66 and 44,
When you do this method, you get the answer
28824, right?
So what you do here, is that add the last '2' to the next digit, which would give 8+2= 10, then add that one to the next digit, you'd get 2904, which is the correct answer. Hope this helps you ;)
thanks so much for this bro
25*45 pls do this using the above method
This man deserves much more than 1 million sub
If I know this now and feel like a genius, how do you feel, thank you so much💜👏🏼
These are amazing!
Thank you so much for teaching and explaining things so thoroughly! I just showed off to my class and they were really impressed. I then taught them everything I learned form you, and it helped our class win the title of Best Class in Mathematics! Now I just need to remember these methods and not mix them up with all the other concepts u have taught 😂
Edit: By the way, I'm now like literally top 3 best in mental math and problem sum solvers thanks to you! Also lots of thanks to my math teacher in school, she teaches and explains things that can be understood almost immediately by the whole class; like you!
oh my god where were you when I was in school!
Yeah, I use the same technique.
It's doesn't work with 24*21
@@olatundeakindeleroberts5369 it does
@@olatundeakindeleroberts5369 504
I've been testing myself with these to lock it down in my mind. I tried a tricky one - 59 x 33 where we have to employ a trick you didn't show and I'm delighted to find I actually got it right! Yay! I can do math!
Peps Haven - What was the trick? I tried 83X24 and did not come up with the right answer.
@@blenderanim8or It's a little hard to explain but 15 x 33 works out to 15 _ 27 at first step. Second step it's 15 + 27 = 42. Third step is where you have to add. So...first number is 1, Second number is 5 + 4 (from the 42) making 9. Third number is 2 (plus the 2 from the 27) making 4. Fourth number is 7. Full number is 1947.
In this video, he doesn't talk about adding carry over's at all. See if this makes it easier.
83 x 24
First step
8 x 2 = 16
3 * 4 = 12
16 ___ 12
Second step
8 x 4 = 32
3 x 2 = 6
32 + 6 = 38
Third step - where you add carry overs.
Start with 1 6 __(38)__ 1 2
First digit 1
Second digit 6 + 3 (carried over from the 38) = 9
Third digit 8 + 1 (carried over from the 12) = 9
Fourth digit 2
Total: 1992
Peps Haven That helped a lot! Thank you, I knew there was something I was missing there. And thank you for being gracious and not snarky like so many on this.
@@blenderanim8or You're welcome. It took me a while to figure out what I was doing wrong too until I twigged. :)
@@pepshaven6520 thanks so much, i will mention u here
I'm able to do these in my head with your method. Thank you,
This is how teachers should had teach me in school 😭
Hahahah
Facts
But they couldn’t, because they were ignorant
The problem is they come up with a certain way of showing work. And you’re forced to do it their way. It’s not about the correct answer, it’s about following rules.
Then later in life you have to teach yourself to work smarter.
You were right in saying that probably half of us watching aren't even at school, I am one of those people haha
I really struggle with math so your video's really do help thank you
Thanks for this! You make me love math.
Your voice was so good had to watch it again.
THANKS A LOT. IT HELPS ME A LOT
OMG! I was searching for this video whole day thanks you saved my life!
It help me so much i should do this everyday because im just an beginner and i like to hear more about maths times,divistion puls and so on i cants believe it
These math tricks are useful. Would you please do a series on *why* these work? That would make them easier to remember, I think. Do the math the long hard way first, then point out what your shortcuts are doing.
(51)(63) = (50 + 1)(60 + 3)
= 50*60 + 1*3 + 50*3 + 1*60
= 3000 + 3 + 150 + 60
= 3003 + 210
= 3213
Open Letter to Educational Systems: teach kids how to do this fast math trick.. the reason why it works is because of distribution.. something that is fundamental for high school algebra.. teaching 4th graders how to multiple like this.. will let them naturally understand how to distribute later.. and we can leave FOIL to mean what it originally meant as a verb (to prevent from succeeding)
Im a student and every friday he would take us a fast multiplication i memorize the multiplication table and i know how to solve multiplication but it takes a minute before i solve that's why im here to learn how to solve multiplication fast and also to improve my mathematical skills i always watch your videos and it thought me many things and also improve my skills,thank you very much sir you're the reason why im top student now.
Thank u so much!!! I really need help with math(I’m below standard on my grades) and this helps me a lot!!! ❤
"I'll rub that out"
We cannot use the underscore all the times.
For example if we get the multiplication of both first two and last two numbers greater than or equal to 10 (As in case of 64*36, we get 6*3=18 and 4*6=24), we will write just four digits not the underscore (1824 not 18_24).
Also if the first number is less than 10 and second one is greater than or equal to 10 (As in case of 34*23, we get 3*2=6 and 4*3=12), we will write just three digits not the underscore (612 not 6_12).
I suggest a few rules for the general equation: ab*cd (e.g; 31*21)
First Step [Let (a*c and b*d) = A]:
1) Don't use underscore:
i) if you get 4 digit number after first operation:
"a*c>9 and b*d>9" (e.g for 64*36, 1824)
ii) if you get first number less then 10 and second greater than equal to 10:
"a*c
Does it matter if AC is > or < 10?
The last 2 calculations should be multiplyed by 10 before they are added.
A= 1824
B= A10
A+B= 20064 =C
What is C?
Just modify it bruh and u carry
FIRST thing you carry
U trying to look smart but you aint
And mpdifiy it on your own if you don't like his
This guy is the Bob Ross of Math.
This one was the best explained!! Thanks! :))
hey that trick is pretty good but do 97 times63 by this method....! i suggest use this method for checking either ur multiplication is right or not
@@salumtummundi9462 9x6 = 54
@@superjojo555 oh yeah
97*63
9*6= 54
7*3 =21
Therefore its 54_21
But we only write the One and keep the two to add it later on there fore it would be like so.
54_1 (The 2 in 21 , Since it's tens will add it later on)
9x3=27
7*6=42
27 + 42 = 69
So,
5 4 _ 1
2
6 9
Equal
6111
Hello, does anyone know how one could solve 127 x 23 using this method? The trick only works with 2 2-digit numbers. How about the multiplication between 1 3-digit numbers and 1 2-digit numbers ? Has he taught any trick regarding this?
I'd say just first do it with the 27*23 and later multiply 23 with 100 and add it up.
tivmego It's difficult to explain this method of his in words or maths, but I'll give it a try.
Suppose that XY is a number (eg for X=2, Y=3 this number will be 23)
and WZP is another number (eg for W=1, Z=2, P=7 this number will be 127)
So X,Y,W,Z,P are just digits.
Now take and write:
(XY) * (WZP) = (X0+Y) * (WZ0 + P) = (WZ*X) [00] + (X*P +WZ * Y)[0] + P*Y
where I put the zeroes in [ ] because what he does is write for each zero-brackets an empty slot: _ _ _
in the 1st slot he puts the number next to [00] : WZ *X (the first numbers of your choice)
in the 2nd slot he puts the number next to [0] : X*P + WZ *Y (the crossings)
In the 3rd slot he puts the numbers without zeros (the two last digits multiplication).
That's his idea... and it is not based in separating the number into the 1st and the 2nd digit, but separating the last digit from the rest of your number.
So let's go to your example:
127 x 23 = (12 x 2 ) [00] + (2 x 7 + 3 x 12) [0] + (3 x 7)
now I will write the numbers in the slots , for that I'll use the bracket for the slots:
[ 12 x 2 ] [ 2 x 7 + 3 x 12 ] [ 3 x 7 ]
[24] [ 50 ] [21]
Now the 3rd slot is larger than 10, so the 2 is going to be added to the middle slot: [24] [52] [1]
The middle slot is larger than 10, so the 5 will be added to the 1st slot:
[29][2][1]
the answer is so: 2921
tivmego You could use his 3-digit trick and make 23 become 023.
or use the lattice multiplication trick.
tivmego
Thanks for the vid mate!
Omg, thanks a lot. I’ve been behind on my math in school but now I really feel confident! 😅
To multiply 3 digits numbers this way Eg: 127 x 23 - use the exact method as in video, leaving out the (100 value) of 127, so work out firstly 27 x 23 = 621 then add your second number (23) with 00 on the end to this: 621 add 23(00) like below.
621
2300 (second number in equation gets 00 behind) ------please read on - it gets exciting!!!
----------
2921
or
156 x 42 (drop the 1)
= 56 x 42 = 2352
2352
4200 (second number in equation gets 00 behind)
---------
6552
If you are multiplying 256 x 42
256 x 42 (drop the 2)
= 56 x 42 = 2352
2352
4200 (second number in equation gets 00 behind)
4200 (add this value twice for every hundred value in your equation)
---------
10752
hmm not needed to write such a long comment just bla bla
i just warn u not to give once morelike that
Neetu Nagula Long comments are needed to explain important things.
😈🙅
Marachenka Ok great method
So when I do 472 x 38, 72 x 38 = 2,736, now use 38 with 3,800, but do that 4 times
Or either just multiply it = 15,200
Do adding so 2,736 + 15,200 = 17,736
Answer would be 17,736
Ok is is good but I saw the other video about that first
thanks marachenka
it's a good method
I calculated my timing
Without method: 1 min
With method : 10 sec
Qiqi Zhang great job!
wut??
im subbing. you are the teacher i been looking for
So what happens when you pick numbers for witch the product of their last digits is greater than 10?
Was searching for this comment bruhh
BRO SOMEONE SAID IT
DO 44 X 57
@@yuvrajbhati4023 4*5=20. 4*7=28. So that is 2028 add 4*7=28. 5*4=20. 28+20=48. So 2028+480=2508 not sure why you add 480 and not 48 but it works!
Thanks.... Kal exam me kaam aaega
One of the first things I learned in doing quick math in your head. Today I ask someone what 8x9 is and the first thing they do is grab their smart phone.😂
Very useful trick, saves a lot of time in calculations, thanks a lot...
At the last one's i had the first one wrong