Math Trick for Fast Multiplication

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  • Опубліковано 4 жов 2024
  • #fastmathtricks
    #mentalmath
    #mathtrick This math trick is pretty easy to do, and can be done in your head faster than a calculator.
    This trick only works when multiplying numbers that both end in five. A couple of simple steps and you're done!
    In addition, the mathematical reasons why this trick work are simply explained at the end of the video.
    To support tecmath on Patreon: / tecmath To donate to the tecmath channel: paypal.me/tecm... To donate to the tecmath channel: paypal.me/tecm...
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КОМЕНТАРІ • 97

  • @benthomas6359
    @benthomas6359 5 років тому +27

    I’m so happy you started uploading again! My GCSEs started this year and these videos are a massive help

  • @mikoajpasnikowski7522
    @mikoajpasnikowski7522 5 років тому +14

    I love this trick! It's so simple and easy to remember + the fact that it works with numbers with 3-digit numbers as well as 2-digit is really helpful. Keep up the good work and thanks for all the help on your channel!

  • @spicychipeater761
    @spicychipeater761 5 років тому +8

    Thank for all you done you helped me through 4rth to 5th grade thank you for everything

  • @sid6784
    @sid6784 5 років тому +13

    Another way of selecting an answer in multiple choice questions is-
    Question: multiply 10x+5 and 10y+5
    Steps- Add X+Y...(a) if answer is even then our eventual answer to (10x+5)(10y+5) will have 25 at the end...(b) if the answer is odd then our eventual answer will be 75
    This way people can eliminate answer choices and select the answer wisely in shortage of time

    • @karinisvetcool
      @karinisvetcool 5 років тому +1

      I've never understood multiple choice math or calculus tests.

  • @RoseAngella
    @RoseAngella 5 років тому +2

    Knowing why it works is a must for me. Thanks for sharing. 💚

  • @MistyyyYT
    @MistyyyYT 5 років тому +7

    Wow I got a test coming and this is what I get amazing!

  • @lukedevlin45
    @lukedevlin45 5 років тому +47

    It sounds like your voice is in constant slow motion

  • @sharonjuniorchess
    @sharonjuniorchess 4 роки тому +2

    I liked the explanation at the end but a visual representation may help people to see what the algebra is actually. doing A rectangle of 35 on one side and 65 on the other can be reduced to a rectangle of 30 x 60 with a band of 5 surrounding it. This band consists of two rectangles (5 x 30 and 5 x 60) plus one square in the far corner (5 x 5). So the total sum/area is:
    (30 x 60) + ((30 + 60) x 5) + (5 x 5) = 1800 + (90 x 5) + 25 = 1800 + 450 + 25 = 2275.
    It was looking at problems like this that helped the arabs to derive algebra; to describe what they were doing.

  • @hichamelattaoui
    @hichamelattaoui 5 років тому +5

    Love it,my 10 years and 8 years will love it and they will be showing off at school 😉 like usual.

  • @seemapatilJapan
    @seemapatilJapan 4 роки тому +1

    very good skills.. thanks

  • @lidamg4074
    @lidamg4074 5 років тому +2

    Thank you

  • @divyoroy9056
    @divyoroy9056 5 років тому +2

    Good job

  • @shadmanameen2270
    @shadmanameen2270 5 років тому +2

    Loved the trick

  • @lavenderlady9942
    @lavenderlady9942 5 років тому +2

    👏👏👏
    Big thanks to you

  • @Rayhid1956
    @Rayhid1956 5 років тому +1

    Very good.

  • @gassics4225
    @gassics4225 5 років тому +7

    Failed maths so now im here :(

  • @psycod2548
    @psycod2548 5 років тому +1

    Mate, thank so much

  • @augustogonzalez6665
    @augustogonzalez6665 5 років тому +1

    You teach me a lot thanks

  • @elizapadua6847
    @elizapadua6847 4 роки тому +1

    Your a wizard math

  • @zanelemazibuko4972
    @zanelemazibuko4972 4 роки тому +1

    can you make bodmas ,exponents ,roots ,functions and relations because my son enjoys learning your math tricks and they have helped him improve in maths

  • @ahnafrahamanchoudhury
    @ahnafrahamanchoudhury 4 роки тому

    I love Maths and Math teachers

  • @kay14042
    @kay14042 5 років тому +1

    As always brilliant
    Thanks

  • @sdavies9060
    @sdavies9060 5 років тому +2

    Nice

  • @noelsingh7065
    @noelsingh7065 3 роки тому

    U r a great math teacher!

  • @fonze5664
    @fonze5664 3 роки тому

    The math nerd in me is totally amazed and enthralled by this dark magic trick 🤓 I'm going to use this every time I have to multiply two numbers that happen to end in 5 in my everyday lif-- oh wait, now I'm sad.

  • @williambunter3311
    @williambunter3311 4 роки тому

    A very handy method. The proof is an example of the benefits of playing around with numbers and discovering new truths about arithmetical patterns! I'm sure that when Pythagoras discov
    vered the right angle triangle equation it was as a result of just doodling around with two squares, rather than from an effort to prove an established theorem.

  • @AndrejNikolov-xw2gi
    @AndrejNikolov-xw2gi 5 років тому +1

    Thank you for coming back!

  • @fat4ll
    @fat4ll 5 років тому +1

    There are nice tricks

  • @MrMr-yy5th
    @MrMr-yy5th 5 років тому +1

    Math trick!!

  • @katherine101able
    @katherine101able 3 роки тому

    Very lovely

  • @jamiehopkinson1597
    @jamiehopkinson1597 5 років тому

    You still upload alot so great

  • @elizapadua6847
    @elizapadua6847 4 роки тому

    Keep a good work

  • @fieryphoenix897
    @fieryphoenix897 5 років тому

    I LOVE THESE

  • @phillipcoppernoll2056
    @phillipcoppernoll2056 3 роки тому

    For the last equation. Just do it like the others. 6x3=18, 6+3=9, Divide by 2= 4.5 .. 18+4.5= 22.5, Then add your 5x5=25 AND the answer is 2275. Right?

  • @Reachermordacai
    @Reachermordacai 5 років тому

    Awesome, thanks.

  • @aishawaddah5311
    @aishawaddah5311 3 роки тому

    Tou are the best in the world

  • @videosrus99
    @videosrus99 3 роки тому

    I must point out that you missed explaining how you arrived at "add 25" in the first problem. Clearly it is 5x5 but you need to explain that and not assume everyone saw that. I actually thought you were going to work out the problem by multiplying 35 x 100 then subtracting 35x5 which is all mental arithmetic. Something my mum taught me about 60 years ago. Not seen your method before and I think it works better than mum's. Very interesting. I am really enjoying your videos. Thank you.

  • @valor36az
    @valor36az 5 років тому

    How awesome!

  • @Nick-yv1wy
    @Nick-yv1wy 4 роки тому

    Bro how does anybody dislike this kind of stuff??

  • @josh5784
    @josh5784 4 роки тому +1

    Yes

  • @sammysidd7806
    @sammysidd7806 5 років тому +2

    I learned lots things!

  • @baileyrichardson5145
    @baileyrichardson5145 5 років тому +6

    LOVE YOU DAD 💙💙

    • @tecmath
      @tecmath  5 років тому +5

      Hey bails....love you too son :)

    • @baileyrichardson5145
      @baileyrichardson5145 5 років тому

      Keep up the great videos.

    • @oRNZYM8
      @oRNZYM8 5 років тому

      @@baileyrichardson5145 thanks i try my best

  • @emmaford5618
    @emmaford5618 5 років тому

    Such a massive help!! Thank you for these step by step guides!

  • @lechaiku
    @lechaiku 7 місяців тому

    the easier way without multiplying by 100 and avoiding decimals:
    45
    x 95
    -------
    4 x 9 || 5 x 5
    36 || 25
    + 6 5 ----> add the average of 40 + 90 (65) and put just before the unit's place
    ----------------
    = 42 75
    135
    x 85
    -------
    13 x 8 || 5 x 5
    104 || 25
    + 10 5 ----> add the average of 130 + 80 (105) and put just before the unit's place
    ----------------
    = 114 75

  • @MrGyges
    @MrGyges 5 років тому

    You brighten my dimness

  • @GodIsEverPowerful
    @GodIsEverPowerful 5 років тому

    pgood. because the no. of multiplications is less! (compared to regular no. of four multiplications) nice

  • @TSSUNIX12
    @TSSUNIX12 5 років тому +1

    45x95 can you solve using this method

  • @mackymadness86
    @mackymadness86 5 років тому

    Love this channel. You sound like a stoned maths teacher but great content

  • @johnryder1713
    @johnryder1713 5 років тому

    Well no matter how long it is since you done one of these videos I'll miss em if it was every day

  • @ericthemadscientist8357
    @ericthemadscientist8357 5 років тому +1

    Huh neat

  • @edwardmiddleton1690
    @edwardmiddleton1690 4 роки тому

    Hey...can you do Constant of Proportionality, please and thank you?

  • @Pablo-dn4to
    @Pablo-dn4to 5 років тому

    Can us do a video of using a square root in ours calculators please!!!

  • @abdulrazack9270
    @abdulrazack9270 3 роки тому

    ** who expected me being 11th grade student in CBSE was looking for this video

  • @joannehall702
    @joannehall702 5 років тому +1

    It would be great if you could add more nursing drug calculation😊

  • @ahnafrahamanchoudhury
    @ahnafrahamanchoudhury 4 роки тому

    Opps! is this for 4- 12?

  • @lizzeelike
    @lizzeelike 4 роки тому

    why u do average? is this trick work for 45X96?

  • @adrianchineaamoros3230
    @adrianchineaamoros3230 3 роки тому

    Sr your system does not work with 23 x 33

  • @selmerrasonable2601
    @selmerrasonable2601 2 роки тому

    35×26

  • @johnng1078
    @johnng1078 3 роки тому

    that's not an aussie accent, that's your voice after eating a meatpie at the AFL

  • @saiabhi9918
    @saiabhi9918 4 роки тому +1

    another wrong method by applying i am getng ok try to solve this
    42*43=1806is actual answer but infact iam gettinh 2006

  • @drax6445
    @drax6445 2 роки тому

    Hi love your classes as it helps me in high school. I am confused with say doing 127 * 86 in my head. So by your trick the first part is 128*8=96 then add (12+8)/2 which I get 106. Then 106*100 + 42 = 10642 but this is wrong. Can please explain. Thank you

    • @itsmemailingyou4234
      @itsmemailingyou4234 2 роки тому

      It only works if the numbers end in 5 (both being half of ten is why it works).
      10*10=100
      5*10=50
      100/50=2

  • @ahmedaboomer7796
    @ahmedaboomer7796 3 роки тому

    what does ( Av ) mean

  • @francescovalente7436
    @francescovalente7436 4 роки тому

    35x95= 35x100 -(5x35) = 3500-175= 3325

  • @sorankurdi1414
    @sorankurdi1414 4 роки тому

    85X33=?

  • @HeavyMetalRuinedMyLife1971a
    @HeavyMetalRuinedMyLife1971a 5 років тому +2

    The spherical trigonometry calculation for globe earth curvature is 8 inches per mile squared....this is demonstrably non existent 😎

  • @platinumknight1
    @platinumknight1 Рік тому

    man im looking for a trick i knew like i could multiply 6.748.123 times 3.968.436 in under a minute and very easy but i forgot what it was

  • @linlove7929
    @linlove7929 4 роки тому

    Loved the trick....you lost me with explanation.....sometimes it’s best not to know why! Love your videos....they help me do my grandsons homework. Thankyou

  • @green_Mascheen
    @green_Mascheen 4 роки тому +1

    35 x 65 =
    3x6 = 18
    Av. (3+6)/2 = 4.5
    18 + 4.5 = 22.5
    22.5 x 100 = 2250
    2250 + 25 = 2275

  • @jacobkris4410
    @jacobkris4410 4 роки тому

    Sounds like the turtle from FInding Nemo.

  • @joannehall702
    @joannehall702 5 років тому +2

    🥰

  • @ItsThatMilkshake
    @ItsThatMilkshake 5 років тому +2

    Doesnt work with 82x75

  • @MicCheckMemoirs
    @MicCheckMemoirs 5 років тому

    Dude I could of used this when I was in the third grade :/, I guess better late than never.

  • @blackbird8010
    @blackbird8010 5 років тому +3

    Damn

  • @hughmacmillan3156
    @hughmacmillan3156 Рік тому

    No answer at the end. 🤦🏼‍♂️

  • @daphnemckayla7676
    @daphnemckayla7676 4 роки тому

    The trick worked alot but the end of the explanation confused me. I got 99.5% right.

  • @TheHdawson
    @TheHdawson 3 роки тому

    I was doing fine until the explanation of why this works- now I'm totally confused with the XY explanation and don't understand. Glad everyone else understands, but, you lost me totally with the XY explanation.

  • @jessesambro9535
    @jessesambro9535 5 років тому +1

    ❤️

  • @ahnafrahamanchoudhury
    @ahnafrahamanchoudhury 4 роки тому

    class?

  • @UneekBruh
    @UneekBruh 5 років тому +2

    Comment🤣

    • @tecmath
      @tecmath  5 років тому +1

      Thank you for it!

    • @UneekBruh
      @UneekBruh 5 років тому

      @@tecmath no worries. Great vid👌

  • @kimberlyroute5983
    @kimberlyroute5983 5 років тому +4

    You lost me after 3300. I have know ideal how you got 25 Not clear at all.

    • @jsaeong
      @jsaeong 5 років тому +2

      Kicking it with Kim KIWK the 25 is just the 5x5 in the ones place

    • @christopherwilson6527
      @christopherwilson6527 5 років тому +2

      Really? Even though he said where the 25 came from multiple times?