How to Divide in Your Head Quickly

Поділитися
Вставка
  • Опубліковано 24 сер 2014
  • Math teacher Charlie Kasov discusses how to divide in your head. Take these tips and tricks and you too will speed up your division.
    Synonym Classroom provides clear and concise answers to common questions in Education, Math, Science, among other topics relevant to today's student and teacher.
    Visit: classroom.synonym.com/ for more information, articles, and answers.

КОМЕНТАРІ • 104

  • @casachezdoom2588
    @casachezdoom2588 2 роки тому +77

    `How to Divide by 5 in Your Head Quickly"
    There, I fixed the title.

    • @NOT_INFILIT
      @NOT_INFILIT 2 місяці тому +3

      Thank you for saving me time

  • @Jack-jj2rv
    @Jack-jj2rv 7 років тому +363

    what if its not 5 haha

    • @ikesau
      @ikesau 5 років тому +20

      I watched this video and scrolled down and reading your comment made me laugh so hard omg

    • @icedragonSg
      @icedragonSg 4 роки тому +2

      thought the same thing lol

    • @jakefenster222
      @jakefenster222 3 роки тому +2

      ikr lol

    • @cosmokram3r246
      @cosmokram3r246 2 роки тому +4

      i saw the video and was trying to do it on paper and I was like WTF. what if I'm not dividing by 5. came here and saw this comment lol

    • @AbdulRehmaanQayyum
      @AbdulRehmaanQayyum 2 роки тому +11

      The idea is to split the numbers to make it easier for yourself. In ÷5, you do (*2÷10). Let's say for dividing by 9, you could divide by 3 twice. In ÷6, you could do ÷2 and then ÷3. These are all tricks and you can use the ones that work for you

  • @danahkim09
    @danahkim09 2 роки тому +51

    I do something like this. If it's like 800 divided by 25, then I know that 25 goes inside 100 four times. And 100 goes inside 800 eight times.
    Then multiply 4 and 8 to get 32, which is how many times 25 would go into 800.

  • @AhmadH345
    @AhmadH345 Рік тому +4

    LOL I WAS DOING THIS TRICK T O MY TEACHER SHE WAS FREAKED OUT SHE WAS LIKE SINCE WHEN DID YOU BECOME A CALCULATOR??

  • @deep_nag
    @deep_nag 6 років тому +28

    It's only by 5 ...please sir give us the process of easy dividing other no.

    • @indev6057
      @indev6057 10 місяців тому +2

      you can do this with any other number For example, 75 divded 3. times 75 by 2 and divide by 6. you just have to double the dividing number which is 3

    • @kelele
      @kelele 4 місяці тому +2

      @@indev6057 Yeah but 150 divide by 6 is not any easier than 75 divided by 3

    • @presidualist4587
      @presidualist4587 14 годин тому

      @@indev6057yoooo u just helped me unlock the path to jesus lmaooo

  • @forreal-sd6gi
    @forreal-sd6gi Рік тому +9

    he is actually writing backwards so we can see.. thats crazy

  • @abigailavalos7088
    @abigailavalos7088 5 років тому +13

    I learned a slower way thank you

  • @johntan8422
    @johntan8422 5 років тому +32

    Yeah but what if I want to divide 1549 by 2890 quickly what do you do?

    • @FluffyMuffs
      @FluffyMuffs 5 років тому +33

      u get a calculator and ram in your head

    • @Red-pv7kx
      @Red-pv7kx 5 років тому +2

      @@FluffyMuffslmaoooo

    • @nooserboyymar8185
      @nooserboyymar8185 2 роки тому +3

      you get good

    • @stephaniehavoksen1761
      @stephaniehavoksen1761 2 роки тому +1

      Well you would have to estimate or use a calculator lolol

    • @artieschmidt3039
      @artieschmidt3039 2 роки тому +3

      @@FluffyMuffs bro the image of slamming your head in the TI-84 had the dying xDDD

  • @Vexilologist
    @Vexilologist 8 місяців тому +1

    Thank you this technique helped my son a lot

  • @CRINGECKILLER
    @CRINGECKILLER Місяць тому +1

    I'm a grown ass man thank you

  • @Gamerz-ue4js
    @Gamerz-ue4js 7 років тому +1

    thank you

  • @lakelaos7298
    @lakelaos7298 8 років тому +1

    Thanks I was bad but your trick works😀😀

  • @DjZephy
    @DjZephy 2 роки тому +13

    i figured this out on my own when i was like 8... what I want to know is how to divide 1 by 24 in my head to figure out what percentage it would be without having to use a calculator

    • @TheShamansQuestion
      @TheShamansQuestion Рік тому +13

      Treat 1 as 100. Since you want a percentage, this should be more natural anyway. The answer will be near 4 because 100 / 25 is 4.
      To get exact, 100 and 24 are even, which is convenient, so simplify by common factors (divide by 2 until you get an odd number on one term). Now you have 25 divide by 6 which is easier. Use your timestables which you should be comfortable with around this area. Answer is 4 with remainder 1/6. How do we get remainder? Repeat process. You might know 1 divided by 6 already (half of 1/3 which is half of 0.3333'). Otherwise, make it 100/6, use timestables to get close or long division in your head, and divide by 100 at the end. 100/6 = 16.66'. Divide by 100 = 0.1666'. Add to 4 and final answer is 4.1666'%.
      *Note:* The decimal answer is 0.0416666', or percentage divided by 100, which undoes our trick at the start.

    • @Imbrokeyay
      @Imbrokeyay Рік тому +2

      @@TheShamansQuestionyou explain better than my math teacher bro i wish you were every one’s teacher

    • @adr3510
      @adr3510 6 місяців тому

      @@TheShamansQuestionthink it was fynman that said once you understand the fundamentals of numbers, you don’t have to remember how to do anything, it just comes naturally. You seem to exhibit what he explains

  • @khasoumi1448
    @khasoumi1448 4 роки тому +9

    Wth..it s for 5 only? I was excited and thought my nephew then it turn out doesnt work on 7-9 tsk

    • @homer4590
      @homer4590 3 роки тому +2

      You multiply by different numbers. For 5 you multiply by 2 and then you can divide by the base (10). For 1 it's 10, for 2 it's 5, for 3 it's 3.333333 (3 and one third), for 4 it's 2.5, for 5 it's 2, for 6 it's 1.666667 (1 and two third), for 7 it's 1.428571repeats (this is a weird one), for 8 it's 1.25, for 9 it's 1.1repeats, and for 10, you're already at 10.

  • @NicoleAndrea-wh6cl
    @NicoleAndrea-wh6cl Рік тому +2

    what if the number isnt divisible by 2 or 10???

  • @vogilisettyakhilkumar9449
    @vogilisettyakhilkumar9449 3 роки тому +3

    Yes it works.. but only for 5 I think..

  • @angelrivas7005
    @angelrivas7005 Рік тому +1

    Now I have the look up a video on how to multiply by 2 in ur head 😅

  • @shubhsharma9260
    @shubhsharma9260 9 років тому

    Its fab I want more such tricks from where do I found more

    • @neofellus1
      @neofellus1 9 років тому +1

      Shubh Sharma Search for tecmath on youtube.

  • @wallywales380
    @wallywales380 8 місяців тому

    how are you that good at righting backwards

  • @Berryxcherrys
    @Berryxcherrys 8 місяців тому

    So the answer must be the lower number in the bigger number in the question

  • @sus-nl6xe
    @sus-nl6xe 2 місяці тому

    the 100 is the chosen one

  • @rishikesh9773
    @rishikesh9773 5 років тому

    nice

  • @Ayesha_c3
    @Ayesha_c3 5 років тому +5

    So i can do it with any numbers🤗

    • @abbywarren1391
      @abbywarren1391 3 роки тому

      Not all but you can with a lot of them!

  • @Berryxcherrys
    @Berryxcherrys 8 місяців тому

    The way to memorize it is
    Divide
    Multiply
    Subtract
    Bringdown

  • @trooper2221
    @trooper2221 6 років тому +1

    How do I dived 1.8 into a number in my head

  • @clarysshow3253
    @clarysshow3253 3 роки тому

    What if the division is 5799/193324

  • @pvp_icebearyt7273
    @pvp_icebearyt7273 7 років тому +2

    is it always needs to multiply by 2

  • @thanutgaming1719
    @thanutgaming1719 Рік тому

    what if it is 57 divide by 7

  • @lucygao7892
    @lucygao7892 3 роки тому

    have a math test tommorow trying to study

  • @grantno308
    @grantno308 6 років тому

    were did the x2 come from I don't get it ?

    • @Sameer-Mustafah-Raza1-2-1
      @Sameer-Mustafah-Raza1-2-1 6 років тому

      What he is saying, it's better to multiply by 2 than dividing. Please watch the video again!

    • @RudivanHemert
      @RudivanHemert 6 років тому

      5/5=1 5x2=10, 10/10 =2
      Because it is easier to divide by 10, you should correct your number. You are going to divide by twice as much, so your number has to be twice as much. If you want to divide by 2.5, and want to make it easier, your can also divide by 10,but the is 4x as much. So you have to multiply your number by 4 first. 2.5/2.5=1 2.5x4/10=1

    • @thegamerchampie8351
      @thegamerchampie8351 Рік тому

      It's easier to divide a number by 10 than 5 but if u divide by 10 without making the 60 a bigger number, you will get the answer wrong, so I multiply both by 2 to make it right

  • @Berryxcherrys
    @Berryxcherrys 8 місяців тому

    Btw im here to. Teach u guys

  • @christophkrass6929
    @christophkrass6929 3 роки тому

    what about 12/11?

  • @Berryxcherrys
    @Berryxcherrys 8 місяців тому

    If u dont know how to divide try to divide the lower number

  • @SuperRamon77777
    @SuperRamon77777 3 роки тому

    Mental secrets for long division ❓

  • @bellamolano
    @bellamolano 7 років тому +2

    I'm in year 3 and I usually get good grades but my grades are falling for some reason

  • @Berryxcherrys
    @Berryxcherrys 8 місяців тому

    So dmsb is dirty markers smell bad

  • @jafarbutt3684
    @jafarbutt3684 Рік тому

    Sir how to 250 divided by 7 in head

    • @Zeitgeist2000
      @Zeitgeist2000 Рік тому

      its going to be 35 point something or 34 point something, all you need to do is figure out how many times 7 goes into 100 then just double it, and then again increase by half of the first number since 50 is half of 100

  • @Berryxcherrys
    @Berryxcherrys 8 місяців тому

    Easyyyy

  • @islamferhat3204
    @islamferhat3204 3 роки тому +1

    Ok,but what if I want to divide 4,678,976 by 123,547,819.See.How do you do that mentally.

    • @AbdulRehmaanQayyum
      @AbdulRehmaanQayyum 2 роки тому +3

      5 million / 125 million --> 1/25 --> 0.04. You can use similar estimations to get close to the actual answer

    • @Marandal
      @Marandal Рік тому

      @@AbdulRehmaanQayyum i managed to get 1/25 but... How did you get 0.04? i'm learning to do math in my head and haven't wrapped my head quite around getting decimals.

    • @AbdulRehmaanQayyum
      @AbdulRehmaanQayyum Рік тому

      @@Marandal I struggled with it too, dont worry, it’s just a matter of some practice.
      Let’s see the easier technique first. Know that you can always multiply things by 10 (or 100) and divide later. E.g: 1/25 -> 100/25 div by 100 -> 4 div by 100 -> 0.04.
      For the second technique, first step is learning the fraction-decimal conversion from 1/1 to 1/10 (like 1/2 is 0.5, 1/3 is 0.33 and so on). Memorize it and ask others to test you on it. Try to use this knowledge while solving cases (almost all case books have cases that use one of these fractions since learning them is important to solve Math mentally),
      Second step involves knowing that fractions beyond 1/10 can be done by multiplying two fractions (or near estimation can be done).
      E.g: 1/16 -> 1/8 div by 2 -> 12.5% div by 2 -> ~6%.
      E.g: 1/25 -> 1/5 div by 5 -> 20% div by 5 -> 4%.
      The second step requires practice (so you do it after Step 1). Once you get a hang of decimal conversions from 1/1 to 1/10, you can start estimating any fraction (even odd fractions. Eg: 1/15 would be close to 1/7 div by 2)
      Good luck! Does it make sense to you?

    • @Marandal
      @Marandal Рік тому

      @@AbdulRehmaanQayyum Wow that actually makes alot of sense! i'm going to start practicing and memorizing some basic %'s like thoes! 1/3(.33) 1/5(%20)
      and some others. Thank you soo much!

    • @AbdulRehmaanQayyum
      @AbdulRehmaanQayyum Рік тому +1

      @@Marandal Anytime buddy, all the best to you

  • @jongonz3939
    @jongonz3939 6 років тому

    ITS SHORT

  • @jessesmith5224
    @jessesmith5224 8 років тому +8

    Is he writing backwards?

    • @os3720
      @os3720 8 років тому +5

      I think after filming the video they back flipped it so we can see the numbers properly and now he looks like writing backwards

    • @SNK1995
      @SNK1995 6 років тому

      Right, the video is flipped, and the proof is the pocket on his shirt, pocket on men's shirt are always on left side. 😉

    • @goobers143
      @goobers143 6 років тому

      SNK that's not true. But the video is flipped.

  • @jongonz3939
    @jongonz3939 6 років тому

    ISN'T THERE A ANOTHER WAY????????????????????????????????

  • @agrimpuriya2585
    @agrimpuriya2585 7 років тому

    Grisp

  • @crikeymos22
    @crikeymos22 5 років тому

    Five us too easy.
    Want an easy trick for 4

    • @bamskies6638
      @bamskies6638 4 роки тому

      Divide number in half 2 times.
      300÷4
      Or 300÷2=150
      Then 150÷2=75.

    • @bamskies6638
      @bamskies6638 4 роки тому

      @Ary Sorry I was actually here on this video for an easy trick for 7 as well. Didn't get what I was looking for but thought I could help out a little with a trick of my own :\

  • @parisaazizi7832
    @parisaazizi7832 7 місяців тому

    i still don’t understand this just do the main thing

  • @kanaya_0936
    @kanaya_0936 3 роки тому

    Why are all of these videos so old?

  • @Solaris4KT4L
    @Solaris4KT4L 7 років тому +1

    What

  • @princessgrace3163
    @princessgrace3163 5 років тому +1

    I didn't even understand a word, bruuh

  • @danchaplin2911
    @danchaplin2911 6 місяців тому

    No explanations given. This is what he should have said.
    If it's 60 divided by 5:
    When you multiply 60 by 2 you have to do it to 5 in order to balance the equation. So now you have 120 divided by 10, which is much easier to calculate, it's just 12 which is the answer. That is the actual explanation. How he has portrayed the maths is terrible and not intuitive at all. 100 years of shame onto this man.

  • @LinDoG678
    @LinDoG678 11 місяців тому

    Even more confused

  • @ArAR-yc1ul
    @ArAR-yc1ul 5 років тому

    Ugh it sucks you did not help me

  • @warrnj4300
    @warrnj4300 3 роки тому

    This video is very detrimnental for ppl learning. fu

  • @lucygao7892
    @lucygao7892 3 роки тому

    WHAT IF ITS NOT 555555 Waste of my time

  • @purealivehappy
    @purealivehappy 5 років тому +4

    Horrible explanation

  • @JamieAlice92
    @JamieAlice92 18 днів тому

    Dividing by 5 is easy. Thanks for wasting my time