I hope you see this. I struggled through my whole highschool. I'm an adult in my 20's now, and I'm finally getting the right meds for my adhd that was never discovered. Despite recieving meds that help me focus, I still have this enormous feeling of being dumb, and lazy since. Anyways, you showed me that hard work can really make me smart too, and im not stuck feeling dumb and helpless.
@@austin529 thanks Austin. I've been a teacher a long time now and I hate school does this to people - where because you think differently it's almost as if you're not welcome right? Be different and think different. It's also a strength.
I feel schools are just too lazy to address all the neurodiversity in students and so they just put you in with the "regular" students, the "gifted" students and those of "special education". Unless you have an intellectual disability that legitimately keeps you from carrying out all the responsibilities of an adult I feel there should be no excuse from teachers or schools to allow students to be disinterested nor be illiterate in maths... That's why I have taken it upon myself to review and teach myself mathematics. This channel makes my journey that much easier.
@@austin529 I teared up a little reading this. I finally got diagnosed this year, even if the meds help me to some extent I can't help but dumb and lazy
Keep in mind that multiplication is a combination of addition as well and as the numbers get larger there are combinations of subtraction addition multiplication can become a factor as well.
You are by far, the greatest most intelligent Math Professor in the Universe! Thank You so much for helping me get back into College. I aspire to become a Teacher as inspirational and driven to teach as you are Sir, thank you so much again.
If the numbers are under twenty - I treat it a bit differently - say for 7 x 18, the tens number is the single digit number (7 ie 70), the unit number is 7x8 = 56. 70 + 56 = 126.
Great videos, I fly for an airline and we use mental math for a lot of things, this will help me to be faster and more accurate at calculations... much appreciated
You can put that into an equation, which can be simplified to this :P : The base number in, for example, 12*14 is 10. Num1 means how far from the base number is the first number (2). Num2 means how far from the base number is the second number (4). (base^2) + (base * num1) + (base * num2) + (num1 * num2) (10^2) + (10 * 2) + (10 * 4) + (2 * 4) 100 + 20 + 40 + 8 = 168
this channels helping me so much I have my SATs soon and we've been doing practice tests and all my correct answers are basically because of this channel XD
For numbers between 10 and 20: The general idea is this: We have (10+a) * (10+b) We then add the units of any number, to the whole of the other number. As is mentioned in the video, it doesn't matter which way you do this, as both will give you (10+a+b). Since this is actually the value of the 10s, we should multiply this whole expression by 10 to get 100+10a+10b. For the units, we multiply the units from the two original numbers to get ab. This is then added to 100+10a+10b to get 100+10a+10b+ab. This of course makes perfect sense if you simply expand the brackets of the original expression: (10+a)*(10+b) = (10*10) + a*10 + 10*b + a*b = 100+10a+10b+ab. But this only really works for numbers between 10 and 20, as mentioned. What if we tried doing it with larger 2-digit numbers? For 54 x 73, the numbers are 44 and 63 away from 10 respectively. We then add 44 to 73 (or 54 to 63) to get 117. We then treat this as the "10s", so we'd treat this at 1170. We'd then multiply the 44 and 63. This is then done the same method: Subtract 10 from both numbers to get 34 and 53. Add 44 + 53 (or 34 + 63) to get 97. This is also the 10s part, so we'd treat this as 970. We then have to multiply the 34 x 53. Repeat the above to get 24 and 43 as the distances from 10. Add 34 + 43 or 24 + 53 to get 87. This is also the 10s part, so this is 770. Then multiply 24 x 43. To do this, again, we add 14 + 43 or 24 + 33 to get 57. This is again the 10s part, so that would be 570 Now we have to multiply 24 x 43. Again, we have 14 + 43, or 24 + 33 to get 67. This is actually 670. Now we're left with 14 x 33. 33 + 4 = 37 (or 23 + 14 = 37) .. we treat this as 370. Now we just have 4 x 23 This is equal to 92. Now what happens if we add everything up? 1170 0970 0770 0570 0370 0092 0002 0440 2500 1000 3942 ... which is the actual answer. Of course, this is far too much work, since we have a chain of constantly multiplying 2 digit numbers, going down by 10 each time.
This is Indian Vedic Maths method. This method works with base 10, 100, 1000 and so on.. You can use this method with other bases also but with some modifications. In case of 54 x 73, Don't use base 10, use base 50. So, numbers will be 50+4 and 50+23 Follow same approach, Multiply 4*23=92 Add 54+23=77 or 73+4=77 either way addition will be same. Now here comes the modification. Because 50 is 1/2 of base 100. Make addition also half, you will get 38.5 As base is 100, multiply number with 100... So, 38.5*100=3850 To get final answer, add 92 in above number.. 3850+92=3942 With practice, you can calculate any 2 digit multiplication orally..
Dear Ocarina: Go to 5:50 he said: 9+17=26 . You can do 9+17 or 7+19 , both will give the same answer which is 26, then you multiply 7by9 to get 63, then you add 260+63= 323. watch again please, to get clear. Thanks
I have just found your channel and very interesting it is too. Although retired now, this quick maths is still of interest .. at least it'll keep my brain active. What's more, I'll be able to keep an eye on what my wife spends .. on yet another new handbag 🤣
There are different videos on different length digits. These are listed in my channel. More material will be released later this year (i'm on holiday at the moment).
HOLY CRAP after watching this i did my own sum and wrote it down and i'm like that can't be the answer way to easy but it was.. thanks man from tassie :P
Thank you Sir! i was a weak at math when i was schooling. didn't score more than 50. anyway i managed to pass the O/L exam really hard. to be honest, math made me hate it. however, now i love learning math by myself.
Over 20 it's possible to do it, but is more complicated. The exact expression is: (first number + second number -10) *10 + (first number -10) * (second number -10) and it's needed to be more time. For example: 36*27 = (36+17)*10+26*17 = 530+(26+7)*10+16*7 = 530+330+112 = 972 36*55 = (36+45)*10+26*45 = 810+(26+35)*10+16*35 = 810+610+(16+25)*10+6*25 = 1420+410+150 = 1980
OR (for any number) like 22X26 (it has to be an odd and even) (You also need to know how to square numbers fast) Find the miidle. 24. 24^2. - 2^2. ( The reason its 2 is because to get to 24 from 22 is 2) So 576 - 4=572. 22X26=572.
en.m.wikipedia.org/wiki/Trachtenberg_system Here is the extended system. There was a book in the 1960s that explained it all, and the life of Trachtenberg, which was a case a great determination through very extreme adversity. I am pleased you are introducing his methods to a new generation: an antidote to the electronic calculator! :)
Even faster way, is understanding the near 10's and addition subtraction 17 x19 = (17 x 20) - 17 children are good with upto 5 multipliers in table, things get's with bigger numbers there after so, 17 x 20 = 340 - 17 = 340 -10 - 7 = 323.
12 x 14. Same as 14 x 10 = 140 & 14 x 2 = 28, so 140 + 28 = 168. That is how I got there in seconds (in my head) at the start of the video. I like your trick though. Thank you.
Man. You never ever disappoint me in the least bit. I've learned so much from your channel in the last few years now.. Great, Great Teaching. Wow!-:)) I'm not so intimidated by math anymore.............😁😉🙂
I teach many people labelled slow learners. Keep practicing, although sometimes a different explanation can help. Good luck!
I hope you see this.
I struggled through my whole highschool.
I'm an adult in my 20's now, and I'm finally getting the right meds for my adhd that was never discovered.
Despite recieving meds that help me focus, I still have this enormous feeling of being dumb, and lazy since.
Anyways, you showed me that hard work can really make me smart too, and im not stuck feeling dumb and helpless.
@@austin529 thanks Austin.
I've been a teacher a long time now and I hate school does this to people - where because you think differently it's almost as if you're not welcome right?
Be different and think different. It's also a strength.
God blessed you. 🙏🙏🙏 Thank you for your teaching!🙂
I feel schools are just too lazy to address all the neurodiversity in students and so they just put you in with the "regular" students, the "gifted" students and those of "special education". Unless you have an intellectual disability that legitimately keeps you from carrying out all the responsibilities of an adult I feel there should be no excuse from teachers or schools to allow students to be disinterested nor be illiterate in maths... That's why I have taken it upon myself to review and teach myself mathematics. This channel makes my journey that much easier.
@@austin529 I teared up a little reading this. I finally got diagnosed this year, even if the meds help me to some extent I can't help but dumb and lazy
i was told i was dyslexic at 27 and have never been able to understand maths till i found your videos which has helped me a lot so thank you!
I had phobia of beautiful girls and after seeing your phone iam bit bit afraid
😂
@@aviattri_9 what da
The fact you think dyslexia means you can't understand maths tells me all i need to know as to why you can't understand maths
I answered them faster than other kids in class,and they were like,WHAT how did you do that so fast😀
That's great keep up the great work.
ultimate flex
Agreed
cannot thank you enough! I am slowly becoming numerate for the first time in my 29 years on this earth thanks to your videos!
Keep in mind that multiplication is a combination of addition as well and as the numbers get larger there are combinations of subtraction addition multiplication can become a factor as well.
I've got other videos showing how to deal with numbers over 20.
Where? I cannot find them.
You are by far, the greatest most intelligent Math Professor in the Universe! Thank You so much for helping me get back into College. I aspire to become a Teacher as inspirational and driven to teach as you are Sir, thank you so much again.
If the numbers are under twenty - I treat it a bit differently - say for 7 x 18, the tens number is the single digit number (7 ie 70), the unit number is 7x8 = 56. 70 + 56 = 126.
Great videos, I fly for an airline and we use mental math for a lot of things, this will help me to be faster and more accurate at calculations... much appreciated
the blokes a legend ... always smiling when i listen to him....
You can put that into an equation, which can be simplified to this :P :
The base number in, for example, 12*14 is 10.
Num1 means how far from the base number is the first number (2).
Num2 means how far from the base number is the second number (4).
(base^2) + (base * num1) + (base * num2) + (num1 * num2)
(10^2) + (10 * 2) + (10 * 4) + (2 * 4)
100 + 20 + 40 + 8 = 168
I preferred his explanation much better
Man your videos are awesome so simple and easy and love how you show the work to the problems , step by step plz keep them coming
Really appreciate your content. I always wanted to know the trick behind quick mental math
this channels helping me so much I have my SATs soon and we've been doing practice tests and all my correct answers are basically because of this channel XD
For numbers between 10 and 20:
The general idea is this:
We have (10+a) * (10+b)
We then add the units of any number, to the whole of the other number. As is mentioned in the video, it doesn't matter which way you do this, as both will give you (10+a+b).
Since this is actually the value of the 10s, we should multiply this whole expression by 10 to get 100+10a+10b.
For the units, we multiply the units from the two original numbers to get ab. This is then added to 100+10a+10b to get 100+10a+10b+ab.
This of course makes perfect sense if you simply expand the brackets of the original expression:
(10+a)*(10+b) = (10*10) + a*10 + 10*b + a*b = 100+10a+10b+ab.
But this only really works for numbers between 10 and 20, as mentioned. What if we tried doing it with larger 2-digit numbers?
For 54 x 73, the numbers are 44 and 63 away from 10 respectively.
We then add 44 to 73 (or 54 to 63) to get 117. We then treat this as the "10s", so we'd treat this at 1170.
We'd then multiply the 44 and 63.
This is then done the same method:
Subtract 10 from both numbers to get 34 and 53.
Add 44 + 53 (or 34 + 63) to get 97. This is also the 10s part, so we'd treat this as 970.
We then have to multiply the 34 x 53.
Repeat the above to get 24 and 43 as the distances from 10.
Add 34 + 43 or 24 + 53 to get 87. This is also the 10s part, so this is 770.
Then multiply 24 x 43.
To do this, again, we add 14 + 43 or 24 + 33 to get 57.
This is again the 10s part, so that would be 570
Now we have to multiply 24 x 43.
Again, we have 14 + 43, or 24 + 33 to get 67.
This is actually 670.
Now we're left with 14 x 33.
33 + 4 = 37 (or 23 + 14 = 37) .. we treat this as 370.
Now we just have 4 x 23
This is equal to 92.
Now what happens if we add everything up?
1170
0970
0770
0570
0370
0092
0002
0440
2500
1000
3942
... which is the actual answer.
Of course, this is far too much work, since we have a chain of constantly multiplying 2 digit numbers, going down by 10 each time.
This is Indian Vedic Maths method.
This method works with base 10, 100, 1000 and so on..
You can use this method with other bases also but with some modifications.
In case of 54 x 73,
Don't use base 10, use base 50.
So, numbers will be 50+4 and 50+23
Follow same approach,
Multiply 4*23=92
Add 54+23=77 or 73+4=77 either way addition will be same.
Now here comes the modification.
Because 50 is 1/2 of base 100.
Make addition also half, you will get 38.5
As base is 100, multiply number with 100...
So, 38.5*100=3850
To get final answer, add 92 in above number..
3850+92=3942
With practice, you can calculate any 2 digit multiplication orally..
Dear Ocarina: Go to 5:50 he said: 9+17=26 . You can do 9+17 or 7+19 , both will give the same answer which is 26, then you multiply 7by9 to get 63, then you add 260+63= 323. watch again please, to get clear. Thanks
I have just found your channel and very interesting it is too.
Although retired now, this quick maths is still of interest .. at least it'll keep my brain active. What's more, I'll be able to keep an eye on what my wife spends .. on yet another new handbag 🤣
If I knew this guy in my first year of college....
mr rouse
Kendrick ross if I did know him i will copy off of him
NO
David Laurance yes it’s about of it
they dont even teach multiplication in college.
Thank you Techmath, I've learnt so much from you. :)
"that'll put the wind right up 'em" - haha gotta love an Aussie maths teacher
I have watched two videos this one and multiplication with 11 and believe me it is awesome....... I really loved your method.... amazing
There are different videos on different length digits. These are listed in my channel. More material will be released later this year (i'm on holiday at the moment).
pretty cool! just showed this to my granddaughter in the second grade having math problems and she was thrilled!
I used to be bad at year 9 maths but since I watched 2 of your videos I became a master thank you
"It's a little trick that only you me and rest of the TH-cam will know about"
Hmm..yeah it's a top secret😂😂😂
Omg. I can now do this quick smart. Its like being given a sharp needle after having used a blunt needle for years. THANK YOU SO MUCH!
hello from usa, thanks
this is a very smart way of showing students much easier and faster it has been avery helpful way to learn i love it this way thank you
HOLY CRAP after watching this i did my own sum and wrote it down and i'm like that can't be the answer way to easy but it was.. thanks man from tassie :P
woooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooow!
Thank you so much!
Dear sir, actually i am not getting understand your language, but i can see your trick.. Hats off... You are the fabulous
This really helps! I don't feel so intimidiatted anymore. Thank you ;)
you have shown the easiest way to solve the regular hard problem. thank U so much.
Omg Man, you helped me a lot, thanks dude!
This whole channel is like arming school kids to take down their maths teachers and I LOVE IT
Nice job although I love a good calculator,you don't need one all of the time.
Thanks
Thank you Sir! i was a weak at math when i was schooling. didn't score more than 50. anyway i managed to pass the O/L exam really hard. to be honest, math made me hate it. however, now i love learning math by myself.
Thank you so much! You made me like math even more!
Over 20 it's possible to do it, but is more complicated. The exact expression is:
(first number + second number -10) *10 + (first number -10) * (second number -10)
and it's needed to be more time.
For example:
36*27 = (36+17)*10+26*17 = 530+(26+7)*10+16*7 = 530+330+112 = 972
36*55 = (36+45)*10+26*45 = 810+(26+35)*10+16*35 = 810+610+(16+25)*10+6*25 = 1420+410+150 = 1980
Thanks for tutorial, you help me improve my mental sums. My basic time table needs refreshing.
It is going to get really interesting when the teacher tells you to "show your work".
I'm happy with that :) Thanks!
Love your methods, thanks for sharing
Or...
13X12
10X10 (always the 100 so just put 1 down)
1
3+2 = 5
15
3X2=6
156
I personally find my method easier, because it's easier to carry
+CoolCreep167 Gaming Thanks. Better in my opinion
OR (for any number) like 22X26 (it has to be an odd and even) (You also need to know how to square numbers fast)
Find the miidle. 24. 24^2. - 2^2. ( The reason its 2 is because to get to 24 from 22 is 2) So 576 - 4=572. 22X26=572.
i just watched this video and was doing it the same way you said at the end from the start :D
You are a credit to humanity.
Your a miracle... Why weren't you around in my high school days
I love this channel!
omg thats awsome now maths is a littel bit easy
what about for instance; 36*27 ? What would the steps for that be?
36×27=6_(4)2
21+12=33+4=37
6+3=9 the final answer is 972 hope you understand even though it's kinda confusing.
Alma Absin I'm confuse
the title said *UNDER TWENTY*
I like your first method much better!!
en.m.wikipedia.org/wiki/Trachtenberg_system
Here is the extended system. There was a book in the 1960s that explained it all, and the life of Trachtenberg, which was a case a great determination through very extreme adversity.
I am pleased you are introducing his methods to a new generation: an antidote to the electronic calculator! :)
wow and before I thought I was good at times tables but now..... THANKS !!!
At around 3:15 you could also add 1+2+1+4, and you get 8. I just figured that out :D
Liked your channel. Its awesome. Great work.
Much love from Canada.
Or
12 × 14
Now,
Firstly, Add 12 to 4 i.e.12+4=16
Secondly, Multiply second digits i.e. 2×4=8
So the answer will be 168
12 *12
12+2=14
2*2=4
144 cool
12*14
12+4=16
2*4=8
Answer = 168
doesnt work.. try 17 x 16.. maybe for multiplication with 12
narasus 17*16
17+6=23
7*6=42
230+42=272
Manmohit Singh thank u
Even faster way, is understanding the near 10's and addition subtraction
17 x19 = (17 x 20) - 17
children are good with upto 5 multipliers in table, things get's with bigger numbers there after
so, 17 x 20 = 340 - 17 = 340 -10 - 7 = 323.
Very impressive! I really feel you are talking to and teaching me! Personally! Very good teacher!
This is amazing! Do you have an app to practice this on I could download?
You're a genuis! Feels like my life has been saved.
Thank you teacher
Thanks mate I'm doing my tests in school and this really helped me out:)
He lost me at hi
😂
Bless this man.
12 x 14. Same as 14 x 10 = 140 & 14 x 2 = 28, so 140 + 28 = 168. That is how I got there in seconds (in my head) at the start of the video. I like your trick though. Thank you.
Or 13x12
Add the 2 to the 13=15 or 150 then add 2x3 =6 answer 156
14x 16
Add the 6 to the14 =20 or 200
Then 4x6=24 answer =224
Another great video thanks a million times
You're so awesome!! Thanks a lot! :D Have a great day, sir!!!!
great and amazing thank you for sharing your idea
Can this channel be monetized? Love your vids
I love that it easy thank you for helping me
Put like on me or you wish you didn't meet me
THIS IS REALLY USEFUL, THANKS A LOOOOTTT
These are awesome! Thanks for help.
you are genius boss
mind blowing ........
superbbbb se b uparrrr
Man. You never ever disappoint me in the least bit. I've learned so much
from your channel in the last few years now.. Great, Great Teaching. Wow!-:))
I'm not so intimidated by math anymore.............😁😉🙂
what if it be numbers like 73 and 62
Under twenty, you can't do that, which is a bummer
MrTheDerper yeah I tried that
4 2 0 6 (7x6) (3x2)
0 1 8 0 (3x6)
0 1 4 0 (7x2)
4 5 2 6
Easy? Easy!
I really want to hug you for this!!!! Thank you so muuuuccchhhh!!!!!!!
Thank you so much best technique ever❤❤❤❤❤❤❤❤❤❤❤
this is so help full
Very good method.thanku sir.
Thank you so much!!
You are a Genius
Awesome trick!
very helpful
I freaking love these
Love you mate.
Thank you, this has helped me out a lot:]
you taught easiest way thank you!!!!!
I love how he mentioned when your in class next, haha I'm 36 and watching all these vids, very helpful 👌
i am a 13 year old and its easy to me so if you try hard u can do it
thank you for helping me
hy
I’m studying for child genius and this helped me a lot
Yes it's a trick, but if you came up with this process by yourself then yes, you're a genius.
i got the first one but i was using your other video!
These tricks are great if you use them frequently enough to remember them readily. Otherwise they offer no advantage over traditional methods.
I love this lads voice.
THANKS SO MUCH!!!!
Thanks mate!