Fast Mental Multiplication Trick - Multiply in your head using base 20 and 30

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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[@Eljulitus]

My life would have been a lot different if you were my math teacher at school. Thanks a lot for your lessons!

[@Ali-fq3nz]

Same here…😊

[@1trucxhondamov589]

When I went to public school, they taught from a curriculum not research or experience! They were there to get a nice pay check!😃

[@davidlewis1680]

Yes I agree , I was terrified of my maths teacher . On a Friday afternoon double maths he’d give me homework and would say learn your times tables and on Monday morning for every you get wrong you’ll get the slipper . I hope he’s sat in hell

[@tecmath]

This technique I studied a few years ago - and many of them I have either known, been shown by colleagues, or funnily enough been shown by students of mine as they try to interpret the simplest method of doing math. Thanks for the question!

[@abdullahmunirnouroz2090]

what bse we use to multiply 3 digit numbers and how to do it??

[@trensic5716]

your students are literally 90000 iq

[@64marcovix]

25x22 can be done with another method which particularly I find easier though I follow your teaching and it works too. So, to multiply any number by 25 keep in mind 25x 4= 100 That means, if we divide the other multiplicand by 4 we get this: 22÷4 ( to divide by 4 just divide by 2 twice!) Thus, 22÷2=11, now again 11÷2=5.5 X10= 550 our final answer! But mentally you can do it in 2 seconds with practice

[@B.editzz]

@@trensic5716 ong

[@GordieGii]

@@abdullahmunirnouroz2090 The first step would be to find the largest multiple of 100 that is lower than both numbers. Let's say the numbers are 254 and 337. 254 = 200+54 and 337 = 200+137 so (200+54) * (200+137) then multiply using FOIL = 200*200 + 200*137 + 54*200 + 54*137 then factor = 200*(200+137+54) + 54*137 = 2*100*391 + 54*137 = 2*39100 + 54*137 = 78200 + 54*137 next use the same trick to multiply 54*137 (you might want to write down the 78200 unless you can memorize it) so 54 = 50+4 and 137 = 50+87 (50+4) * (50*87) = 50*50 + 50*87 + 4*50 + 4*87 hmm. I don't like 4*87, so how about this 54*137 = (54*2) * (137/2) 108*137/2 = (100+8) * (100+37) / 2 = (100*100 + 100*37 + 8*100 + 8*37) / 2 = (100*(145) + 8*37) / 2 = (14500 + 8*30 + 8*7) / 2 = (14500 + 240 + 56) / 2 = 14796 / 2 = 7000+350+45+3 = 7398 +78200 (remember?) = 85598 Tada! Of course 4*87 isn't really that bad so 50*(54+87) + 4*87 = 5*10*141 + 4*87 = 5*1410 + 4*87 = 7050 + 348 = 7398 same as the other way

[@GeorgeSPAMTindle]

I am hooked, just love this stuff. I am pleased that there are so many viewers, it's good to see it's not just me then who finds this stuff exciting!

[@Khonic23]

Reverend George well yes, there's over 7 billion people on earth and at least 40% have internet access. You're obviously not going to be the only one interested lol

[@ianc8398]

Khonic would that be 2.8 billion people interested?????

[@bigberthayourbff6255]

But not all 2.8 people who have internet access are interested. Maybe even the people who *dont* have internet access are interested. You never know what goes on in people’s minds.

[@vrsce0178]

@@Khonic23 How many people you know that are interested in math or learning in general that go as far to look up videos on YT on math? 😂You know this generation doesnt find interest in actually using the internet to learn

[@RAIDFIX]

Thanks my friend. I'm nearly 60 and really enjoyed learning a new technique. Will find this very useful. You have a patient teaching style too. Cheers

[@supersmasher3619]

chopper hello

[@krishnavavhal7443]

chopper

[@jeffayoe7468]

@@krishnavavhal7443 chopper

[@saeediearcher7339]

he sounds excited when he talks its so cool

[@tonybarfridge4369]

saeedie archer maths can be exciting

[@hugolevaillant5208]

@@tonybarfridge4369 math is exciting

[@darpanrajput9651]

@@tonybarfridge4369 uUhuio0

[@Mr_Wiley]

I now feel like a wizard. KZbin just obliterated all my early years of early math education in less than 30 minutes and 2 videos. I'm buzzing in excitement as an adult.

[@RoselineJerryA]

yess also see 3blue1brown

[@charley408]

🤯🤯🤯🤯🤯🤯🤯🤯🤯🤯 I know right! My mind is blown, and that's not easy to do!

[@charley408]

@@RoselineJerryA ???

[@PurplePassionPaper]

Me too!

[@ditto1051]

Same here!

[@katiemorris9711]

Now my day wasn't completely useless.

[@matrixfull]

same ^^

[@kevinv.5961]

Katie Morris same

[@i.am.tavisha.m]

same bro ^^^^^

[@iwouldliketobelievethattha7561]

i misread the name as Kamala Harris lol

[@UmarAlFarooq]

If you smile at someone, your day will never be useless.

[@legend519]

I'm studying for the PCAT and needed to learn to multiply without a calculator (sadly I've become dependent on them). This video has helped A LOT. Thank you!

[@jasperbutcher2596]

100% agree. Hey looking back, I hope you did well!

[@liamichellequiroznunez5396]

Same!!

[@betselotaderaw83]

same here man

[@Myce]

Same. I take it in 2 days. Scored a 75 on my practice test but I have self confidence issues and am uneducated in simple math

[@user-gz2ri9by4x]

Me too😊😊👍

[@katmiranda7687]

I FEELL LIKE A MATH MASTER EHEHEHE. Spent 2 hours practicing your method. Thank you. I'm feeling more confident about my mental math now. THANK YOU. I LOVE YOU DUDE.

[@georgigeranov9778]

Goodness gracious! I wish someone had taught me that in my school years... Still it's a good mental exercise. Thousand thanks!

[@ryanfrancisco179]

I have never calculated in my head faster than today. I am forever changed for the better.

[@thenextshenanigantownandth4393]

Every since I was young iv'e had massive phobia of maths, due to my dyscalculia. Your videos were a massive help, thanks.

[@tecmath]

Thanks for commenting - this happens in the next part video - base level 50!

[@godiseverything1482]

Can you do a video on functions? I would appreciate it. You make Math seem so easy.. Thank you

[@_unknown_3768]

Hi 👋 I am 14 and this September I am going into year 10 and I’m always getting nervous coz I felt like I might fail math but omg I stumbled across your channel and honestly I am so grateful I have you teach me better than my teachers and I can do it at my own speed I have learnt things in less than 1 hour . I have subscribed to you , your amazing and I can’t wait to watch more videos this helps me a lot ! 😊

[@aztecwarrior1421]

I am 64 and enjoying this stuff. Thank you sir!

[@jamesmacgregor2838]

Your channel is amazing! After years of getting by with minimal basic math skills I decided to make some changes. Your channel is an inspiration. You make learning so much more enjoyable and natural. Now I'm getting into physics and algebra and I'm loving it! If you had told me 2 days ago that I would be multiplying double digits in my head I would have told you that you were crazy! Awesome job!

[@banniemccormick4971]

I just wanted to thank you for posting these videos....I have never been so fast at math before!!! Thank you so much for sharing your wisdom!!!

[@eepohce]

I cannot stop watching this series. This should definitely be taught. I couldn't imagine doing 2 digit number multiplication in my head before this yet it's so simple. Well done.

[@dominiccharles6987]

he's got a nice way of speaking and a soothing voice. thanks a lot.

[@EzkPalacio]

Thank you SO much, you are an amazing person. I learned so much more in TWO days of watching your videos than I did in the 4 years of high school!!! I'm definitely subscribing. Your accent makes the videos much more entertaining! Once again, thank you.

[@jamespaul4618]

Your insights and techniques regarding mental math and multiplication are greatly appreciated. This is very empowering. Thanks for sharing these concepts.

[@kellycrites80]

This is so helpful to not only myself but my middle schooler since he has been virtual schooling since March 2020. Along with your other videos you have made helping him with math so much easier. Cheers!

[@healthsignalllc3456]

Thank you sooooo much! I love it plus when having to be patient (like waiting in line) I like to make up numbers and do them in my head. I’m looking to get real fast at it. Thank you again!

[@timeforamazingchest5271]

This will be a huge help for day-to-day stuff. Thanks a lot!

[@ends.paradox]

I know you made this a long time ago, but I struggle with mental math and multiplication, so I completely avoided it because it made me feel so stupid. Thank you so much for helping me, these tricks are super helpful! wish I knew about you when I was younger :)

[@tomalcolm]

This is great. I’ve always done something like this for easy numbers by rounding and then adding or subtracting the difference, but this is more efficient with fewer steps, and I can do it with less simple numbers.

[@nathandaniel5451]

Thank you, this will help me alot since i am in grade 8. On the side I done: 19 x 26 = 494 32 x 27 = 864 43 x 37 = 1,591 52 x 38 = 1,976 64 x 71 = 4,544 106 x 98 = 10,388 43 x 51 = 2193 13 x 8 = 104 512 x 497 = 254,464

[@gmwire1935]

good for you

[@MyBigThing2010]

On a side note, I've* done... On a side note, I have* done... On a side note, I *did do these/this.... On a side note, I have also completed....(Best choice.) Now pay attention in English class (punctuation and grammar) and you'll be good to go!

[@michaelempeigne3519]

I am amazed that you did these and got them all right including some which were not covered in the video such as 106 x 98

[@aliciad4283]

Brilliant! I am so thankful. Finally a way to simply and quickly do math that is conceptual and leads to mental math!

[@A.double93]

thank you so much. iv just started a new job as a junior design engineer, i cant believe how rusty my simple problem solving has become over the years in sales! love the videos not to much not to little and a touch of dry humour

[@HungNguyen-dl9nl]

Love this video. I been doing the long way in my head. Now you just help me to do multiplication in my head way faster. 👍

[@shriyashaw1430]

I'm not showing this to anyone. I really wanna beat my friend in maths and now I can. MUAHAHAHA.

[@giofts7497]

Shadow 88 Me Too... MUAAAAHAHAHAHA

[@i.am.tavisha.m]

me too

[@smithblack7939]

Your friend already knows the trick . MUAHAHA.

[@mrhoneybadger5539]

@Jarod David They probably fat after the 2 years.

[@HarrisonEkeblad]

You're an absolute legend, thanks for this.

[@jules4349]

That’s literally mindblowing! Thank you so much

[@_sonicfive]

Now all I need is an opportunity where multiplying 78 x 56 comes up so I can impress people. Sadly I don't remember a time this was useful besides school.

[@educatedonealways6281]

If you don't find math useful then you are just dumb or in a dead end career

[@stelahmuinde4322]

I always get fascinated by this math tricks, good work and keep up!

[@malcolmoliver7678]

Omg! I am in love with this technique. I totally plan to use this strategy for my GMAT! Thanks again man!

[@iwouldliketobelievethattha7561]

Good Luck!

[@LigerDJ217]

ok so i maybe in year 11 right now and i am starting to see my grades drop when i study alot, so i started to search how i can improve my maths and when i found your videos and started to watch them it made my mind start up again. so i thank you for helping me change my studying habbits for when i have my final full year exam some time at the end of the year. Your Examples really help my mind think like it was in primary school. Thanks TecMath

[@djnAbNo2]

This is brilliant, I'm so glad I came across this! No more reaching for the calculator when impossible looking numbers show up ^^

[@aleksitolonen2274]

This is a really fast way to count these in your head! Thank you.

[@Patriot41776]

These are amazing. Thank you so much. Wish I knew this 20+ years ago FFS! Well done sir and g’day to you!

[@LENUS2]

Unbelievable. Perfect method. Thanks. Liked, Subscribed

[@treygillott2212]

you're literally getting me ready for my aptitude test for the navy. love your vids chief

[@bcnicholas123]

this is gonna help so much in finance, thank you

[@PrideofPitchers]

Go Tigers!

[@UmarAlFarooq]

You have given me a great gift! Thank you! If only I had known this so many years ago!

[@idreesismail591]

I've been watching you for long time and your videos are perfect mate thanks keep up the good work👌

[@shimolagdameo1891]

Goodday mate! Thank you for the amazing technique!

[@JoaniRayl]

It's amazing how much this helps!

[@magickbytheocean24]

For the fear of multiplication on a vetassess test, this technique has now given me greater confidence. Thank you.

[@faisalrajahussain1414]

I am working towards Pilot Aptitude Test and these videos help me a lot when it comes do doing math questions without calculator.

[@seemapatilJapan]

superb technique for mental multiplication. Thank you

[@Maria-hh2vm]

Thank you, this helpled me so much!

[@jedics1]

In less than an hour this channel made me better at maths than a decade of it at school did....Im probably still going to use my phone though because it doesn't make silly mistakes like me :)

[@buzzwerd8093]

I had to go back to algebra because set in my ways to see what you're doing. Wow that's a nice rearrangement of binomials!

[@judychong438]

Amazing methods, I can do my sums in no time now, thank you so much for the tutorial

[@suriyaprakasam5560]

Easy understanding & nice

[@DJ-cm3zm]

I am speechless, Thank you

[@alefcoimbra1440]

Amazing trick! Thank you very much!

[@leonhuck8949]

You help me a lot with my head math issues. Thanks for that.

[@1wholovestrees]

You are a great teacher for this old gal. I got many of these right! The next to the last group especially and the last one.

[@kalin83]

Brilliant hope ill never forget this tough.

[@GrimRawr]

I love that he gets right to the important parts of the information. I feel like Khan academy had all these extra thoughts.

[@trintp1686]

I really hate math but when I watch yours and try to do it myself. OMG! It is really fun and fast. I will try to teach this tip to my Thai students in English class. You are the first Math teacher who I subcribed.

[@connorking984]

Dang, I've always been good at mental maths, I developed my own method and I'm probably the best at it of anyone I know personally but this is probably faster given some practice refining this. Awesome, looking forward to learning more!

[@skiffyjoes8586]

Thank you very much x36 tec you have helped a lot of young minds in castlemaine i know that you do this to help people and this is just another comment reminding you its working, your giving people i care about a better chance. simply cant put into a chat bar how much that means to me and them

[@joechiou8888]

Very interesting! (X+A)*(X+B)= X^2+(A+B)X+AB=((X+A)+B)*X+AB, very smart!!! Very smart way to use algebra!!

[@lialukman6475]

This is amazing...Love it!!!

[@magickanaxs7360]

thank you man you blow my mind I can't stop to watch. now I will teach it other.

[@whoisluke]

I no longer feel behind in my class!! Thank you so much

[@malihajani1679]

Thank you so much for this video! This is really awesome and easy, it helps me alot

[@iamerica655]

Best method ever. I just solved a base 200 problem this way and got it completely right the first try.

[@eekwhodat7122]

Mindblown... Validation of my struggles with math late in grammar school and through high school. Not that I was "dumb" but the teaching technique and presentation were so wretched.

[@jack-zx1hu]

THIS IS SO GOOD!

[@yourstruly7845]

thank you so much!!! we need these in school ☺️🙏👍

[@dashyz3293]

I incredibly loved this video, thanks a lot!

[@ashirwadgrcharoonrashid3907]

I am from India, I enjoyed your way of teaching very much

[@argenis7323]

this is a really interesting metod, very usefull thanks a lot.....

[@hazelbradford4224]

Wow! Just love it! Math is one of my passions.

[@dicedrice7216]

Thank you for making math fun!

[@WiNLAD_]

Thank you A LOT it was really useful god bless you hope the best for you

[@MichaelKeaveneyYouTube]

Your IQ is ∞×∞. Seriously, I'm considered a genius and you actually teach me things I don't know yet. You're Einstein.

[@dannie3117]

I am really enjoying getting back into math without a calculator. Thank you

[@kishorecoelho3186]

I enjoy your presentation. Thanks

[@CandiceAlane]

Thank you for this!

[@lazmonroy8165]

Your videos are awesome. So easy to follow

[@bradleymusuamba3228]

Your a smart guy!!You must be gifted.

[@BB8-seesaw]

Thank you so much for the video, and it actually works and isn’t hard to understand.

[@stewarthanna4419]

this is awesome so far

[@Tamim1994]

Very nice explanation and very nice technique!

[@nandiniagarwal9040]

Brilliant, thanks so much!

[@vincentinbox]

This is just awesome, thanks a lot for posting them. I am teaching these methods to my nephew who is 7 and he is loving them. Not to mention I LOVE them a lot. Thank you SIR

[@PeachyNanaUK]

Aged 68 I’ve learnt how to multiply large numbers in my head. Yay. Was always able to multiply up to 12 x 12 in my head and some other easy ones but this is great!

[@mskellytolar]

Mr. Tech Math man's voice is so dreamy :-)

[@SenpaiTorpidDOW]

This is fantastic.

[@MrSF247]

This vids are great! Thank you for posting!

[@pablitomauricio]

Love this thanks so much this is really gonna help

[@rooflessmofo]

Brilliant. This is so much fun.

[@lederic]

This is Owesome!

[@Mr99deepak]

you are superb!! hat's off boss!!

[@ferretadam]

Great video man it helped me loads.

[@SungazerDNB]

Thank you so much, I actually get all this! I sucked at math in school because fear got the better of me.