I came across this site last week as I was looking for some math tricks to help my daughter that is in 4th grade. She was having a hard time multiplying the old school way but after about 15 minutes...she had this method hands down...and the sense of pride she felt after knowing this method is great...I look forward to seeing your other videos....Thanks again !! YOU ROCK
The benefit of knowing a number of ways to do a problem is to be able to pick the most efficient method for the problem at hand. In simple examples like 15 x 12, it's a perfect problem for multiplying 15 x 10, and then adding that to 15 x 2. Just about everyone can multiply by 10 or 20, so use that familiarity, and then the rest of the problem is just multiplying by a single digit.
Go left to right and it speeds up estimations also! 24x14 = 20x10 = 200 + the criss cross 20x4 + 4x10 = 80 + 40 = 120, so now you have 320. Last is 4x4 = 16 + 320 = 336.
24x14=(20+4)x14= 280+56 = 336. We can also multiply in Blocks, 24x14= 14x4=56. We take "6" and "5" is carried out. Now, 14x2=28 plus carried 5= 33. So by joining, we get, 336.
With the 30X12 problem, I went through all of your steps and figured out the answer was 360 before you were halfway through explaining it. It wasn't until then that I realized all I had to do was multiply 3X12 for 36 and bring down the 0 to get 360. It's not a critique... just another method of getting the same answer. I think this way is GREAT for the other numbers!! I just need more practice using Mental Math shortcuts so that I can remember them!
You may get problem if you begin at the middle when digits are large like 3 4 5 digit multiplication with cross multiplication. But it also a quite good idea, thank you 👍👍👍
In Vedic Maths it's called vertically and crosswise. Can be used even for multiplying 2*3 digits or 5*5 digits, When one number has a digit or two less you just add zeroes at the beginning of that number to make digits equal.
This the best technique to do it. So much easier than that bother crap, where I have to put 3 column numbers and then adding. That really does my head in.
It's all pattern recognition, which means practice practice practice. Which means the amount of time to calculate will vary a lot. 97x86 would take me 20 or so seconds, but 13x17 takes me about 2 seconds ((17+3)10+7x3=200+21, so 221) All of the tricks are patterns, and more you practice more patterns you'll find. As well as you'll iron out weaknesses you probably didn't realise you had. To embarras myself it turns out that I didn't know my times-tables. So I practiced that. And then I realised that I actually was faster at doing 24+163 than 6+8 (my brain would "lag " for an extra second for the latter, and it turned out it was because the it was faster to do 4+6 and 4+3 than it is to do 6+8 because I didn't actually have all my 1 digit multiplication memorised very well.
Or 13x12 13 + 2=15 multiply by 10 =150 Plus 3×2 = 6 add together = 156 12x13 12 + 3 = 15 multiply by 10 = 150 Plus 2 ×3 = 6 add together = 156 Try this on any 2 digit number between 11 and 19
Thta's a great method with some numbers but with all the examples you choose, I was able to do it more easily - admittedly I grew up at a time when there were no calculators so we developed strategies for mental maths, eg 25 x anything, add two 0's and divide by 4
If you look at the digits of the two numbers: ab and cd: you get (10a + b)(10c + d) and you result with 100ac + b*d, this is the equivalent of what mathtutordvd is saying (I love this guy's tutorials!!)
Thanks for your comment. Yes, anytime you are multiplying a multiple of ten such as 20 or 40, or 50, etc then the math will be much easier in your head. The beauty of the method in the video is that it works for all 2 digit numbers. Thanks!
For 2 digit numbers up to 19 there is an easier method. Ex 1. 12 x 13. Just add 2 to 13 or 3 to 12 = 15. first part of answer. the 2x3 = 6. last part. Answer: 156. Ex 2. 14 x 15. Add 5 to 14 or 4 to 15 = 19. then 5x4=20. Carry 2 to 19. Answer 210
I think the big problems are very hard to solve mentally. I am all good if I have the original problem written down, but if I have to remember it, as well as my calculations, I start to slip up. Any tips on how to practise?
Learn to do your calculations from the left to the right. That way you can say the answer as you calculate whilst adding the smaller numbers to your running total as you work your way across to the units. Practice doing it on paper this way as well as in your head. Also look at the numbers to see if they can be done more easily by breaking one of the numbers down into its factors and then doing two single digit multiplications.
I have a bit of an easier idea. Why not go 150+30 to get 180 220+44 = 264, 130+26 = 156. Work from left to right instead and add the extra digit '0' all the time.
"You can't just write a two digit number answer because your going to get numbers that are too large" Actually that is the secret to doing left to right calculations in your head. You just have to separate your product sums with a comma or slash (on paper or in your head) and then rearrange (or carry) the number so that there are single digits in each column.
Oh my gosh sir! You are very very helpful and I appreciate you making these videos to help people. This is just way easier than what they teach in school I don't know why they haven't learned these tricks yet... But I can Amaze my teachers and classmates with these tricks. Thank you sir. 👍
Do you have any advice for people who slightly with dyslexia? Do you think it is still possible for people who slightly struggle with both math and reading to find this possible?
You call it criss-cross! Lol Hey, It's already common knowledge that it is one of the 16 Vedic formulas of Vedic math. There are dozens of books written on Vedic Math. And this method which u call criss-cross is applicable to 2 digit, 3 digit, 4 digit and all kinds of numbers not only 2 digits. Its real name is Urdhva-Tiryak Sutra. And yup u can use Vedic maths for fast calculations and even fast algebra or geometry. Try it.
Lol he never said that he is telling us something that he discovered himself. He just told us the easy way already known to many people in the world which still many people don't know. Secondly yes it is one of the vedic mathematics tricks and yes u named the sutra right too, but why mock him for that. He is just teaching it to common people who want to learn mental Maths or are nt gd with Maths. They don't want to know the exact name of the sutra they r using or from where it is actually derived etc. So please be a little more polite. At least he is helping some people out there unlike u just mocking him without helping anyone. And also dude it's not common knowledge
Vedic Mathematics is a book written by the Indian monk Bharati Krishna Tirtha, and first published in 1965. It contains a list of mathematical techniques, which the author claimed were retrieved from the Vedas and supposedly contained all mathematical knowledge. These claims have been since rejected in their entirety.
The fastest way to multiply 51x41 in your head is the same digit method in this problem 1 is the common digit but it's the unit one so this is how it works first is to multiply the tens digits 4x5=20 then put two zero's like 2000 the next step is to add the tens digits and then multiply the common digit witch is one then put a zero and add 4+5=9x1=90+2000=2090 then the last step is this 1x1=1 2090+1=2091
There is an easier way for 2 digit numbers... for example : 75*24 you do 75*(20+4) -> 75*2=150 then add a 0 to it so 1500 , now 4*75=300 so 1500+300=1800
U DO NOT UNDERSTAND HOW MUCH I NEEDED THIS THANK YOU!
I came across this site last week as I was looking for some math tricks to help my daughter that is in 4th grade. She was having a hard time multiplying the old school way but after about 15 minutes...she had this method hands down...and the sense of pride she felt after knowing this method is great...I look forward to seeing your other videos....Thanks again !! YOU ROCK
You’re an amazing teacher! Wow this gives this senior citizen a definite edge. Thank you💐
The benefit of knowing a number of ways to do a problem is to be able to pick the most efficient method for the problem at hand. In simple examples like 15 x 12, it's a perfect problem for multiplying 15 x 10, and then adding that to 15 x 2. Just about everyone can multiply by 10 or 20, so use that familiarity, and then the rest of the problem is just multiplying by a single digit.
Go left to right and it speeds up estimations also! 24x14 = 20x10 = 200 + the criss cross 20x4 + 4x10 = 80 + 40 = 120, so now you have 320. Last is 4x4 = 16 + 320 = 336.
Janet Mitchell Yeah. It's basically binomial multiplication: (20+4)(10+4). This is what I usually do, and it works great!
24x14=(20+4)x14= 280+56 = 336.
We can also multiply in Blocks, 24x14= 14x4=56. We take "6" and "5" is carried out. Now, 14x2=28 plus carried 5= 33. So by joining, we get, 336.
You need to do all such calculations in Mind. We Indians can do this, that's we are great.
This is really helpful when you want quickly arrive at an estimated value.
With the 30X12 problem, I went through all of your steps and figured out the answer was 360 before you were halfway through explaining it. It wasn't until then that I realized all I had to do was multiply 3X12 for 36 and bring down the 0 to get 360. It's not a critique... just another method of getting the same answer. I think this way is GREAT for the other numbers!! I just need more practice using Mental Math shortcuts so that I can remember them!
if you dont like carrying in your head then do the problem using the same method BUT from right to left instead to left to right.
You right 👍👍👍
@@orangejuice5668 and if you like a little bit of carrying but not too much then start in the middle
You may get problem if you begin at the middle when digits are large like 3 4 5 digit multiplication with cross multiplication. But it also a quite good idea, thank you 👍👍👍
I know @orange juice. He’s a RUclips and he’s a gamer
Thank you, this is very interesting and very practical. where were you when I was in high school??!!
lol I impressed my friends a lot when I said I could multiply any numbers in under 30 seconds. They were like what the hell.
Can you do it under 6 secs?
@@Ik1Wetniet with practice, yes
No swear or mom beat you or do i
Is it hard bro
When I was at 6 I can do that
And now I can do that in 10 secs
I’m impressed when I watched this..whe tf am I seein this nowww?
This is the greatest piece of information pertaining to arithmetic I have ever seen!! I love you man
Great method, things like this help people become more mathematically capable and my students will be have another tool to use. Thanks
In Vedic Maths it's called vertically and crosswise. Can be used even for multiplying 2*3 digits or 5*5 digits, When one number has a digit or two less you just add zeroes at the beginning of that number to make digits equal.
This the best technique to do it. So much easier than that bother crap, where I have to put 3 column numbers and then adding. That really does my head in.
Best multiplication trick I've seen!
your right its amazing
All your videos are asome thankyou so much now I feel much better cuz I now know a short way to do the problems without burning my brain:)))
I didn't understand two digit multiplication and I always had to use an area model but know I know how to thanks to you!
This is actually really amazing! :)
It's all pattern recognition, which means practice practice practice.
Which means the amount of time to calculate will vary a lot.
97x86 would take me 20 or so seconds, but
13x17 takes me about 2 seconds ((17+3)10+7x3=200+21, so 221)
All of the tricks are patterns, and more you practice more patterns you'll find. As well as you'll iron out weaknesses you probably didn't realise you had.
To embarras myself it turns out that I didn't know my times-tables. So I practiced that. And then I realised that I actually was faster at doing 24+163 than 6+8 (my brain would "lag " for an extra second for the latter, and it turned out it was because the it was faster to do 4+6 and 4+3 than it is to do 6+8 because I didn't actually have all my 1 digit multiplication memorised very well.
Or 13x12
13 + 2=15 multiply by 10 =150
Plus 3×2 = 6 add together = 156
12x13
12 + 3 = 15 multiply by 10 = 150
Plus 2 ×3 = 6 add together = 156
Try this on any 2 digit number between 11 and 19
I can multiple 45895x36783 in just 10 seconds by using this method of Vedic Mathematics.
You have changed my life bro thank you and may God bless you 💝
Thta's a great method with some numbers but with all the examples you choose, I was able to do it more easily - admittedly I grew up at a time when there were no calculators so we developed strategies for mental maths, eg 25 x anything, add two 0's and divide by 4
Amazing! Never knew about this method !
+GiftedHeart :) Really? This is just the usual school method for long multiplication, just made in a fancy fay.
Bon Bon
Hi bon bon! I love mlp too 😃 I came back to this video because I randomly remembered it 🤣
If you look at the digits of the two numbers: ab and cd:
you get (10a + b)(10c + d) and you result with 100ac + b*d, this is the equivalent of what mathtutordvd is saying (I love this guy's tutorials!!)
Wrong check it again
Thanks for your comment. Yes, anytime you are multiplying a multiple of ten such as 20 or 40, or 50, etc then the math will be much easier in your head. The beauty of the method in the video is that it works for all 2 digit numbers. Thanks!
For 2 digit numbers up to 19 there is an easier method. Ex 1. 12 x 13. Just add 2 to 13 or 3 to 12 = 15. first part of answer. the 2x3 = 6. last part. Answer: 156. Ex 2. 14 x 15. Add 5 to 14 or 4 to 15 = 19. then 5x4=20. Carry 2 to 19. Answer 210
William Wheeler
Omg. I learned something new. thank you!!!
I think the big problems are very hard to solve mentally. I am all good if I have the original problem written down, but if I have to remember it, as well as my calculations, I start to slip up. Any tips on how to practise?
Learn to do your calculations from the left to the right. That way you can say the answer as you calculate whilst adding the smaller numbers to your running total as you work your way across to the units. Practice doing it on paper this way as well as in your head. Also look at the numbers to see if they can be done more easily by breaking one of the numbers down into its factors and then doing two single digit multiplications.
This is so fantastic It's taught me so much
looking up how to teach multiplication for my 4th graders.... didn't know i would learn so much for myself instead! thanks for this!! :)
Thx my friend is really quick at math so I can’t wait to show of this method
I have a bit of an easier idea. Why not go 150+30 to get 180
220+44 = 264, 130+26 = 156. Work from left to right instead and add the extra digit '0' all the time.
Thanks that was very well precented, Cheers, Pete
Love this math trick😍😍 thank you so much it helps me alot😘
it really helped me good job
"You can't just write a two digit number answer because your going to get numbers that are too large" Actually that is the secret to doing left to right calculations in your head. You just have to separate your product sums with a comma or slash (on paper or in your head) and then rearrange (or carry) the number so that there are single digits in each column.
Wow thanks to this video, my mom will be impressed of my math now lol
Love it! Thank you so much!
thanks for sharing your knowledge or tricks
oh my gosh my mom is to busy to teach me so i watched this amazing video thanks
I absolutely LOVE this! Thanks for sharing.
awesome...................................just love this trick!!!!!!!!!!!!!!!!!!
I think it easier to do your method but reverse (start by the power ten than go to the unit )
Thanks for sharing. Can u also share how to solve addiction n subtraction mentally with easy method.
Really helped me thank you very much.
I am impressed with your video 🥰
Nice concept sir ..love you
Best technique EVERRRRRRR!!!!!!
But question: what is the cris-cross technique for 3 digit numbers?
Very impressive, great discovery
1:00 this is for the people who need to go back to a technique.
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Thanks So Much works like a treat ☺️
This Guy never misses Good job 🔥🔥
Add right column for the last digit
Criss cross multiply then add the the next the last
Multiply left column for first digit
I am going to do this to my friends and make them go crazy to try to figure out what i did
I sucked at math till I watched this video. Thank you so much for saving my brain!
That video has many knowledges I learn thank u very much
Mind blowing thankyou so much
Its vedic maths technique
Thanks
Oh my gosh sir!
You are very very helpful and I appreciate you making these videos to help people.
This is just way easier than what they teach in school I don't know why they haven't learned these tricks yet...
But I can Amaze my teachers and classmates with these tricks.
Thank you sir. 👍
Really cool video and I have a question:are you an actual teacher, what school do you teach in
I often do math for fun.. This technique is very very helpful... Well done, great video.
Amazing, thanks 🙂
i already know but i still watched and learned..
30*12 is much easier done by rewriting it as (3*10+3*2)*10 = (30+6)*10 = 360.
This is pretty amazing
wow thank you so much, i feel like a boss with this
You're cool man .... it helps a lot.
Nice technics
Do you have any advice for people who slightly with dyslexia? Do you think it is still possible for people who slightly struggle with both math and reading to find this possible?
Yea. just have to work 5 - 25 percent harder
You call it criss-cross! Lol Hey, It's already common knowledge that it is one of the 16 Vedic formulas of Vedic math. There are dozens of books written on Vedic Math. And this method which u call criss-cross is applicable to 2 digit, 3 digit, 4 digit and all kinds of numbers not only 2 digits. Its real name is Urdhva-Tiryak Sutra.
And yup u can use Vedic maths for fast calculations and even fast algebra or geometry. Try it.
Lol he never said that he is telling us something that he discovered himself. He just told us the easy way already known to many people in the world which still many people don't know. Secondly yes it is one of the vedic mathematics tricks and yes u named the sutra right too, but why mock him for that. He is just teaching it to common people who want to learn mental Maths or are nt gd with Maths. They don't want to know the exact name of the sutra they r using or from where it is actually derived etc. So please be a little more polite. At least he is helping some people out there unlike u just mocking him without helping anyone. And also dude it's not common knowledge
But you're batman! I wanna know your secret identity.
Vedic Mathematics is a book written by the Indian monk Bharati Krishna Tirtha, and first published in 1965. It contains a list of mathematical techniques, which the author claimed were retrieved from the Vedas and supposedly contained all mathematical knowledge. These claims have been since rejected in their entirety.
very very helpful!!
Thank you very much
This is my new favourite channel
My friend's been carrying around a mental math book to fool me-now I can fool him,thanks to you!
This vid is VERY helpful. ❤❤❤❤❤❤
Great!
this is the best tutor ever
fantastic
Very powerful indeed. 👏🏽
THANK YOU SO MUCH SIR
Totally gonna help my unteachable friend! SHE WILL GET AN A +
Thank you I was struggling with this today in school
Well done
That's vedic math! I'm learning that now, it's awesome! Wish they taught it in school.
So happy you liked it!
Today is the competition. Wish me luck!!!
We tend to read most things from left to right, therefore it's better to begin on the left.
Thanks for your tutorial!
But how about 3 digits or more?
Thank you
Thanks a lot
The fastest way to multiply 51x41 in your head is the same digit method in this problem 1 is the common digit but it's the unit one so this is how it works first is to multiply the tens digits 4x5=20 then put two zero's like 2000 the next step is to add the tens digits and then multiply the common digit witch is one then put a zero and add
4+5=9x1=90+2000=2090 then the last step is this
1x1=1 2090+1=2091
Wow, thanks sir
Man you the best thank you for sharing your value time👑👑👑😁😁😁😁
thabks for this but my braincells are now dead. lol
Wow
Effectively I think this method is good
THANKS
thx 4 dis i had real trouble in math
prepping me for my professional skills test bit by bit
It would be better for estimation if we multiply left to right.
Works with the most significant numbers first
Thx it teally help me a lot!😍
Just simple calculation. I never see this method before. Maths still impressive me...
There is an easier way for 2 digit numbers... for example : 75*24 you do 75*(20+4) -> 75*2=150 then add a 0 to it so 1500 , now 4*75=300 so 1500+300=1800
its innacurate sometimes
amazing!!!!!!!!!
could you use a similar method with addition?
r u dumb?
No question is a stupid question.
thank you sir
effective one!