Fast Mental Multiplication Trick - Multiply in your head numbers near 50
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- Опубликовано: 11 сен 2024
- This mental multiplication trick uses the idea of a third number - a base number - to help us multiply two numbers in your head. This series of videos first looks at multiplying numbers near 10 using base 10. The second video looks at multiplying using base 20 and 30. The third video looks at how to apply this mental multiplication trick to numbers near 50. The forth video the investigates ho to easilt mentally multiply numbers near to 100. Continue your mental math multiplication abilties here!
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its so much easier learning from your videos than under a pressured school environment, im learning so fast and picking up everything i missed in school.
Simple distributive property works for any number pairing
23X21 = (23)(20) + 23(1) = 460+23 = 483
53X51 = (53)(50) +53(1) = 2650 + 53 = 2703
YOU DESERVE SO MANY MORE VIEWS!
thank you for these videos they are AMAZING
I really love how you added the idea to halve the number first, before multiplying by 100 - I think it's easier that way. Thanks again, this is so awesome!
Many thanks for the insightful method! Funny - after watching base 10, base 20/30 and base 50 I asked a friend to give me a multiplication problem with 2 numbers where each number was > or = 59 and I would solve it in my head in less than 30 seconds, she said ok "36 x 16" ..... I approached it with base 20, absolute perfect pick on her part!
S4gggà
Multiplication rizz
I`ve been out of school for years now and this has changed how I do math. Thank you so much
Thanks for the comment. Alas, no - this idea is one I learnt years ago from a book (called become a math genius or something like that!)
Where did you learn to have such a nice voice?
i wonder if that book exist now, the one made that book must be a genius
Thank you tecmath, I can now solve problems such as: 37x13 under 5 seconds in my head, wonderful technique. I already had a glimpse of the technique but I didn't realize I could use it without one number being number 9. Then again I was 12 at that time.
This is the first time in my life I have enjoyed doing maths.
maths no longer taste like burning
choochoo
Next stop :: English / proper use of the pluralses :)
Sounds sarcastic but he didn't misuse any plurals?
"enjoyed doing maths" "maths"
I've watched all of the videos, I think they're amazing, I can work these sums out so much quicker now, thank you so much. You're a star!!
Love your math videos! (always bad at maths, never thought I would hear myself say I loved it!) Thanks so much for turning my head around at 71. :)
Now, supposing we'd chosen the use the more difficult difference, -4/5.
It still works, but it's more difficult to do mentally.
So, 17 -4/5 = 16 1/5 = 16.2
Since we're using the right-hand difference, we now have to multiply by the right-hand (secondary) base of 100: 16.2 x 100 = 1620
The rest is the same. Multiply the (unmodified) differences: -3 x -4 = +12
Which gives: 1620 +12 = 1632
These videos are so awesome.Like someone else said,the first time I've ever enjoyed doing math.
Now i am always getting full marks in my multiplication tests.
I will tell you a trick
1- 96 is near from 100 with -4
2- 17 is near from 25 with -8
3- divide 4 by 4 = 1
4- subtract 1 from 17 = 16
5- multiply 16*100=1600
6- multiply -4*-8=32
7- Add 32 to 1600 = 1632 This is the answer.
Another Example to understand 92* 23 ok
1- 92 is near to 100 with -8
2- Divide 8/4=2
3- 23 is near to 25 with -2
4- Subtract 2 from 23 = 21
5- Multiply 21 * 100 = 2100
6- Multiply -8*-2=16
7- add 16 to 2100 = 2116 Hope this helpful to you
Rather than say, 50x100/2 it may be easier to do 50^2 in that example. This can be used for any numbers which are the same distance from the base. IE 66x74= 70^2-6x4=4876 (subtraction is used because one number is less than the base)
The general algebraic method is:
(10x + y)(10x + z) (this represents the two 2-digit numbers)
The units values of the two numbers are y and z respectively.
We then cross add the units from one number to the whole of the other number.
For obvious reasons, it doesn't matter which way you do it. This is because if you add the z to the 10x + y, you get 10x + y + z, and if you add the y to the 10x + z, you also get 10x + y + z.
We then, multiply _that_ number by 10x. We then get 100x^2 + 10xy + 10xz.
Then we multiply the units digits to get yz, and add this to the rest of the answer to get 100x^2 + 10xy + 10xz + yz.
How does this work? Well, what if we just expand the brackets using the "FOIL" (first, inner, outer, last) method?
(10x + y)(10x + z)
First = 10x * 10x = 100x^2
Inner = y * 10x = 10xy
Outer = 10x * z = 10xz
Last = y * z = yz
Add them together and there you go.
i think this is the simplest method to solve multiplication
thanking you techmath
After watching a couple vids for a few weeks, my new passion is math.
cheers mate ! so much fun to finally be able to do some math!
You're the best!
i think using base 50 is much easier now! thanks Sir!
23*21= 4 6+2 3 483
51*53= 25 5+15 3 2703
Wonderful to see this math being done this way...thanks.
Speechless how easy this is, when you do it a lot you literally can calculate in 3 seconds, if you do it a lot
I watched 2 of your videos and I know it In one day you are a good math teacher
GREAT, your sharing is incredible, everyone saying oh I saw this, ooooooo.k, but tecmath shared. thanks you keep this up, you are so clear. I am taking my teas in 4weeks, I have already learned so much from three videos, thanks!!!!
Great question!
Look in my video responses!
you should learn how to reply lol
but i love your math tricks
:D
Love ur maths trick bro....I watch this about mil time👍
AMAZING FABULOUS OUTSTANDING MAGNIFICENT
Thanks a lot! Your videos helps me a lot in my school, please keep up the good work 😊
Right at this moment, I realize that math is essential for a respectful life
Nice, very helpful. I didn’t know this although I do know a trick to multiply by 50 and it works really well.
Does it involve multiplying by 2?
No we substitute 50 with 100/2. If there is a remainder then we put a 50 at the end. I have a video on it in my channel.
Great Vedic method. Thank you for sharing the knowledge. Practice makes perfect.
Great
I would have liked to know it at school
Thanks
Great stuff mate keep it up :)
Please what of if I want to multiply 19*57. How do I go about it?
Thank you... my students who despise math will be elated.
forget the base.
ab*cd = ac ad+bc bd
I like it! Wish I'd had tins years ago, I'll pass it on.
When the numbers are the same distance from the “base”, use difference of squares.
52 × 48 = (50+2)(50-2) = 50² - 2² = 2496.
You deserve so much more credit than you get
Ya true
53*54=25 35 12 = 2862
Just memories the multiplication table
Outstanding videos.
21*17=2 15 7= 357
This actually works with any number near any number and so on
and even easier to say 21*23 is 1 less than 22 squared. Likewise 51*53 is 1 less than 52 squared etc... 💕
Great teaching mindset.
This is such a great way to think about maths
what about numbers beyond 59? does it works the same?
Great method, thank you very much. Keep up the great work!
It is better when you just multiply the sum of the added number by the tenth's place digit. Haha example 52x57 where its nearest is 50 so just looking at 50, I'll get the 5 which is in the tens place and multiply it by (52+7), shortening the process haha..
These are simple but I find it difficult to remember the numbers in my head as I'm going along and doing them. So I have to go back and do it again...it's frustrating.
i've found it to be quite easy, but everyone is'nt alike so yea
I agree
Say the number you're "place holding" out loud to yourself while learning. Eventually you will stop talking to yourself when it becomes trained in the brain. You're welcome.
Keep trying, this is a good way of building a stronger working memory. Don't get frustrated!
Lucy P same:(
I did the 42 x 49 = problem by using 40 base....this is great to know and make things easier.
Doesn't appear to be any links to other videos!
Which method do you use for 65 * 82?
thanks
You’re not making sense 23×21 you get 48 and add zero explain that to me because I get 24 and then you say double it what am I doubling? I don’t understand what you mean by so I’m stuck at 24 and then I get it wrong
Your still helping people out with this video including mee 😁 thank you
You are so much better than my math Teacher
sir, i loved ur these three consecutive videos. but im getting stuck when im multiplying 43 with 63. how am i gonna do that if i take the base as 50? also, what am i going to do while multiplying 34 with 85?
I realize that this question was asked 3 years ago, but i'm glad you asked it because it really gave me an opportunity to test my grasp of this concept, and it gave my mind something to do while i was on the toilet lol.
The first one kinda follows the examples given in the video. Using base 50, 63 is 13 over, and 43 + 13 = 56, so we're working with 56 x 50 = 2800. Then you subtract (50-43) + 13 = 91, giving 2709.
That second one was super tricky. Mostly because you have to store numbers in your head because the process needs to be done twice. But using base 50 again makes it somewhat easier, because of the shortcut that goes with it.
So i had to start by storing 34 in my head, and then saying those numbers are (-16) and (+35) from base 50. But now you need to multiply those numbers, so you use the base 20 trick. So 35 - 4 = 31, giving us 620, then subtract (4 x 15) to get 560.
So then we recall that 34 we had tucked away, add 35 = 69, shortcut using base 50 again to 3450, then subtract the 560 for the final answer 2890.
I kept getting stuck when i was trying to store the 3450 in my head and then trying to calculate the -560 afterwards, so i had to do it backwards to make it work. And even when i finally got it, it was by no means a fast process, but i imagine it can get faster with practice.
Anyway, thanks for the challenge!
Excellent , marvellous, thank you for the tutorial, I am so fast at my maths now
Thank you sir , you are really genius
God, I wish teachers would have taught this when I was in school....so much easier.
when you say 2 x 7 it looks like plus signs on top instead of times simbles. iam getting the hang of some of your tecmath videos.
Hi , I find it very good tricks when the BASE is very similar almost with the same *"DECENA"* ~> 51. and 54 , 39 and 46, 79 and 84.... Decena are 5&5 , then 3&4 and at least 7&8. But I apply other calculations to do it in head. Its boths good.
great video, but this method does start to break down a little if you have something like 16 * 58 ? You could choose base 30 but this becomes a little trickier in your head.
Very Good
Very helpful.How do I check your Video response?
Thanks for this. Really cool.
Very helpful . Thanks a lot
What if you use 40
best channel on YT
Voice cannot be heard properly. Speak loudly
better method is to take for example 47 * 53 =
1. Multiply First two digits and multiply by 100
4*5 = 20*100=2000
2. Multiply the first digit of each by the second digit of the other number and make the sum
40*3 = 120
50*7=350
120+350=470
3. Multiply the second digits
7*3=21
4. Sum it all together
2000+470+21= 2491
How about 31.25x66.86x99.12x .67x99.99 = ?
i got perfect. thank you for easy math trick. i learn't a lot ♥️
Its funny to see the number of people who gave up on this method by looking at the number of views on each video
This is actually a method in Vedic Math referred to as "Base Multiplication."
Why did you repeat the question "53 x 48"?
Kindly improve the audio sound, thank for teaching nicely
You are a Genius my friend!
This only applicable if both numbers involved are similar in size (how about 84 x 24?)
Enjoy your presentation.
i want to apply your math skills in real life!
the sound quality is extremely bad
very very informative video .....useful to me ...... thank sir !!
i love the take meth channel its so cool
thank!
Good stuff! But what if you have to deal with numbers like 98 x 24. What base should you use in that case? It appears to be significantly harder. Is there a special method for these kinds of problems?
98 is 2 away from 100. 2x24 is 48. The answer is 48 short of what 24x100 would have been, so 2352.
Hi, only now I readed to you. In this case is little bit more complicate but its possible to calculating it too on head. You can *choose* the BASE that you want example to multiplication 24●86 you could choose base 10 or 20. If for example you will choose *"20"* you hade : 20●(86+4★★) + (4●66)= 20●90+264= 1800+264= *2064* . How you see you can choose the *"base"* that you want, but more FAR will be the BASE between they 2 number, and more bigger will be the number to calculate it. Its was good my explication? Ps... with this★★I mean that you could use *66+24* ,the results will be always *90* , ok? ~~>> *66* is the difference between *86 & 20* , and who *4* is the difference between *24 & 20* , ok?
So after my example try to resolve your 98●24...... in this case you could use *base 100 or 20* . 100 is more easy, but try make with boths ok? But you can use the 3. method: if *a=24 and b=98* you have ~> a●b= a●{(100-(100-b)} 24●{(100 - (100-98)}= 24●(100-2)= *(24●100) + 24●(-2)* = 2400-48= *2352* very easy not?
I worked through the 10s, 20s and 30s fast and did the questions with no problems but the 50s gave me a bit of a problem.
Watched you do a math problem, sq root of 2x/2 =2. Is it still up on RUclips??
Thank you!!
Exxxxxxxcellent . . . .
What do you do when the numbers aren't the same like 54 *28?
I've been trying numbers above 59 and the numbers don't add up. 62x63=3906 not 3256 (3250 + 6). Any suggestions? Thanks.
use base 60
this man is a god
sunai nehi deta kiya bolate aoja tho thoda jada kara.
Can someone point out to me where the “links” are for the other videos mentioned here?
Glad I came across this! Absolutely love this!
But +2 and -2 will get cancelled naaaa?
what if the base numbers are far away like 22*48 or 17*54?
use the base thats kinda in the middle and they should even out and it schould become quite easy again
Then make it your base 40 where 22 is lacking -18 and 48 +8 and so on trust me it faking works his video teaching superb works
Gatsby O. what if I 19*98? use 50 as a fucking bases?
li shunchuen 1,862. Did that in my head, but it took like 5 mins. Used 50 as base 😊
li shunchuen consider 19 as 20 like ( 20 times 98 which is 1960 ) then subtract 98 from the total ( 1960 minus 98 which 1862 )