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How to work out the HCF and LCM using factor trees

January 16, 2012 by Simon 293 Comments

Factor trees are useful way of showing numbers that divide into the larger number.

They’re basically a picture with the number at the top and its factors below.

So, if we look at the number 42, a typical factor tree could look like either one of these:

Factor Trees

Notice that the second line in both trees are different. These are still factors of 42 but, if you follow it through to the third line, you’ll get to the prime* factors. These are the numbers we are interested in.

Multiplying them together will give you the original number, so 42 = 2 x 3 x 7

The idea is that the prime factors will allow you to calculate:

  • the HCF – meaning the Highest Common Factor. Where you have 2 or more numbers, it is the largest number that will divide into both. Really useful for simplifying fractions.
So: the HCF of  108 and 72 is 36.
How to work with HCF

2 / 3 is a bit easier to deal with!

  • the LCM – meaning the Lowest Common Multiple. Great for adding and subtracting fractions.
How to use HCF

See how to add fractions for more details.

Most GCSE factor tree questions are grade 4 and valued at around 4 marks. Although there are a couple of methods to calculate HCF and LCM.

 

Watch these and try the quick test

How to work out the HCF – the easy way

 

How to work out the LCM – the easy way

 

How to work out the HCF and LCM using factor trees

 

An alternative method is to use short division. It’s quite useful and can be used with algebraic equations relatively easily 🙂

How to work out the HCF and LCM using short division

 

LCM Word problem Lars, Rita and Alan

 

* Prime numbers are numbers that are only divisible by themselves and one. In the factor trees shown 2, 3 and 7 are all prime numbers. Click here for How to work out prime factors of a number for a quick reminder.

 

Watch on YouTube:

How to work out HCF – the easy way

How to work out LCM the easy way

How to work out the HCF and LCM using factor trees

How to work out the HCF and LCM using short division

LCM word problem Lars, Rita and Alan

 

Comments

  1. Zainab Jokhio says

    September 28, 2015 at 2:35 pm

    this video really helped thank you.

    Reply
  2. Adebayo Olorunfemi says

    August 16, 2015 at 4:24 pm

    please thank you love your teaching

    Reply
  3. Sukhdev Saini says

    August 15, 2015 at 1:00 pm

    This video is very helpful. thank you so much…….

    Reply
  4. Seshemt Tchetab says

    July 22, 2015 at 11:49 am

    He left out 2 in 12

    Reply
  5. Nagajothi K says

    July 13, 2015 at 1:59 pm

    It is a very useful clip. Next time do PRIME FACTORIZATION.

    Reply
  6. Julia Sutter says

    July 6, 2015 at 1:49 pm

    Thanks that helped me a lot. I’m going to have and exam tomorrow

    Reply
  7. Atharv Nidhi says

    July 3, 2015 at 5:20 pm

    I passed yaay it’s all because of u sir,u r the bestest

    Reply
  8. Jasper Mohan says

    June 23, 2015 at 7:44 pm

    what about 2 in 12

    Reply
  9. ammad hamza says

    June 16, 2015 at 10:07 pm

    Thx u helped alot

    Reply
  10. Hassan Maroc says

    June 14, 2015 at 11:32 pm

    Thanks got end year exam tomorrow 15/06/15 year 8

    Reply
  11. Aayza The Unicorn says

    June 11, 2015 at 8:15 am

    2:41 “Make sure you have all the factors” He missed out 1 as a factor for
    12 =^.^+
    Other than that thanks! 😀

    Reply
  12. michael oreilly says

    June 9, 2015 at 10:11 pm

    Thaaaaaaanks!

    Reply
  13. rajiv gupta says

    June 6, 2015 at 11:20 am

    good!!

    Reply
  14. Abhishek Patil says

    June 6, 2015 at 5:07 am

    Thanks 🙂

    Reply
  15. Eric3279 says

    June 4, 2015 at 3:18 am

    This helped me so much! LCM was a blur in my mind until I saw this vid!

    Reply
  16. Charlotte Smith says

    June 3, 2015 at 8:30 pm

    Thank you, this really helped me

    Reply
  17. Dan ny says

    June 3, 2015 at 6:08 pm

    Thanks, I’ve got maths GCSE tomorrow and needed to go over this. Helped a
    lot and made it interesting. (Well as interesting as maths revision can be)

    Reply
  18. Thamer Aldegailby says

    June 2, 2015 at 7:42 pm

    thanks man you really helped me

    Reply
  19. Ryan Douglas says

    May 31, 2015 at 4:09 pm

    I found this really helpful

    Reply
  20. Forza 5 Gameplay says

    May 28, 2015 at 12:42 pm

    2 things. The person who invented this method is a genius and secondly,
    isn’t there a separate technique for calculating the LCM?

    Reply
  21. padraic fitzsimons says

    May 27, 2015 at 8:34 pm

    ThAnks a lot

    Reply
  22. Ana Martel Forcano says

    May 27, 2015 at 6:06 pm

    Thank you very much because i didn´t now how to do it and know i now and a
    got a very good grade in my test THANK YOUUUUUUUU

    Reply
  23. Movie Maker says

    May 25, 2015 at 1:44 pm

    Sorry but isnt 2 a factor of 12 also?

    Reply
  24. Evelyn Houseman says

    May 23, 2015 at 10:03 am

    really helpful. thanks 😀

    Reply
  25. Breno Bivar says

    May 17, 2015 at 10:41 pm

    Man you saved me before a math test thankyou

    Reply
  26. themba nsingo says

    May 15, 2015 at 2:46 pm

    BRILLIANT!! My lecturer has been trying to explain this to me forever…. I
    only just got it now. Thanks!! you’re a rockstar!!

    Reply
  27. ellie peng says

    May 13, 2015 at 9:02 pm

    thanks, this really helps, i’m doing end of year exams and this is a really
    helpful and easy way!

    Reply
  28. Ziyan Baloch says

    May 13, 2015 at 6:17 pm

    This helped a lot. There was another video which was good, but i deduce
    that this one was just a little better. Do you use prime factors so you
    don’t get “interference” trying to manipulate with the correlating factors
    that just get the thing messy? Also, how does that trick work where you
    find the LCM by multiplying the remaining factors and the result of finding
    the HCF?

    Reply
  29. Atharv Nidhi says

    May 13, 2015 at 5:45 pm

    thnx

    Reply
  30. Matt Crane says

    May 10, 2015 at 1:45 pm

    I finally got it thank you very much

    Reply
  31. Usman Naeem says

    May 9, 2015 at 10:57 am

    youre pro in this !!!!!!!……….my teacher explained a long method!!!

    Reply
  32. Ejay Dee says

    May 9, 2015 at 9:35 am

    Thanks Simon, this was well explained and really helpful for my stat
    assignment…cheers 🙂

    Reply
  33. Betty wong Wong says

    May 5, 2015 at 2:20 am

    My last name is Simmons

    Reply
  34. Gigi Tsai says

    May 2, 2015 at 10:51 am

    Thank you so much! This helps heap

    Reply
  35. Gamer Doge says

    May 1, 2015 at 7:55 pm

    Thank you so much, I appreciate the help! 😉

    Reply
  36. Zoe Hutchinson says

    April 29, 2015 at 12:05 pm

    this helped so much!, my maths teacher is crap….

    Reply
  37. Sarabjit Singh says

    April 26, 2015 at 1:45 pm

    Check out this video on YouTube:

    Reply
  38. sidsood98 says

    April 25, 2015 at 1:59 pm

    could you help me with the help me with the LCM of the following terms
    A=3^4*5^2, B=2^2*3^3*5^2 and C=3^2*5^3*7 I worked it out as
    2^2*3^5*5^3*7 but the markscheme does not agree could you please help me
    out. ASAP

    Reply
  39. ilLinoiSe says

    April 23, 2015 at 11:38 am

    thanks i can now finish homework HELPED ALOT!!

    Reply
  40. Daniel Moran says

    April 19, 2015 at 7:00 pm

    so helpful cheers

    Reply
  41. WeLsH WiZaRdZz says

    April 16, 2015 at 5:51 pm

    Finally found an easy way. Cheers this’ll help for my maths gcse

    Reply
  42. Mauricio Gil Bejarano says

    April 12, 2015 at 2:36 pm

    thank you so much

    Reply
  43. Saleh Najeeb says

    April 9, 2015 at 9:19 pm

    Well it’s good but for 12 2 is also a factor

    Reply
  44. Jonathan Ngo says

    April 2, 2015 at 10:35 am

    So good

    Reply
  45. Alex Paul says

    April 1, 2015 at 5:34 pm

    Really helped thanks! Used to be really good at them in Primary school but
    didn’t do them for 2-3 years and got rubbish! But im good now! THANKS

    Reply
  46. iona horton says

    April 1, 2015 at 2:08 pm

    Thanks this helped me so much with my mats revision!My maths teacher taught
    it me a way which I didn’t understand, and this has really helped 🙂

    Reply
  47. Ezo Playz says

    March 29, 2015 at 10:29 am

    Thnx i really needed to refresh my memory

    Reply
  48. Caleb Dewing says

    March 25, 2015 at 1:36 pm

    a lot with homework better than my mum would explain it

    Reply
  49. sravani pvn says

    March 21, 2015 at 6:47 am

    LOL!!! what about 9??? 😀

    Reply
  50. Annastasia Nicol says

    March 19, 2015 at 2:09 pm

    Thank u so much my maths teacher does not explain it right im in grdb8 and
    I onky figured it out now

    Reply
  51. Matthew grant says

    March 16, 2015 at 7:35 pm

    thanks this helped

    Reply
  52. nichlous soomaru says

    March 16, 2015 at 12:52 pm

    when doing fractions ,finding the lcm is and alternative method? iv seen it
    done with out lcm so they are different methods, i wanna know which one
    would best suit me.

    Reply
  53. Timothy Savva says

    March 15, 2015 at 11:07 am

    thank you so much you helped me so much

    Reply
  54. Muhd Adam says

    March 9, 2015 at 1:18 pm

    Ty

    Reply
  55. Chaz Cole says

    March 5, 2015 at 7:14 pm

    Thanks it helped me a lot in my homework!

    Reply
  56. wilson law says

    March 5, 2015 at 11:06 am

    THANKS, you helped me so much 😀

    Reply
  57. Kinki Poon says

    March 2, 2015 at 2:25 pm

    Thank you so much! It makes me feel better now,haha.

    Reply
  58. makaveli don says

    February 27, 2015 at 4:07 pm

    hats off 4 u. u made it so easy .

    Reply
  59. james chapman says

    February 25, 2015 at 11:13 pm

    This doesn’t work?? For example I tried doing this with 36 and 84?? And I
    got the hcf of 6 when infact the correct answer is 12?

    Reply
  60. Binesh Singh says

    February 25, 2015 at 1:41 pm

    Thank you again:)

    Reply
  61. Binesh Singh says

    February 25, 2015 at 1:40 pm

    This really helped…thank you

    Reply
  62. josh palazzo says

    February 24, 2015 at 9:15 am

    thanx now can finish homework

    Reply
  63. Noah Chatz says

    February 24, 2015 at 5:33 am

    You missed 2 in the factors of 12

    Reply
  64. liam rumble345 says

    February 23, 2015 at 3:24 pm

    thanks this helped me so much

    Reply
  65. ajoksable says

    February 19, 2015 at 6:24 pm

    Lovely God blessed you, you are the best un saludo desde Huesca,

    Reply
  66. Sarah Jarvis says

    February 16, 2015 at 6:29 pm

    Thank you! You explained it way better !!

    Reply
  67. Drone Films says

    February 11, 2015 at 9:24 pm

    Thanks really helps when I forget how to do things in math.

    Reply
  68. PROGamer says

    February 5, 2015 at 4:32 pm

    Thx I’ll remember that coz in my test today I got it wrong

    Reply
  69. hsvstheuniverse says

    February 4, 2015 at 9:03 pm

    How does a factor tree work if the number goes into decimals. Could you
    please help I would really appreciate it. Thanks

    Reply
  70. mae wickham says

    February 3, 2015 at 7:01 pm

    doesnt 2 go into 12???

    Reply
  71. matthew tomlinso says

    February 2, 2015 at 9:26 pm

    Cool amazing asome

    Reply
  72. DeannaLuvDeidara AJ says

    February 2, 2015 at 1:31 pm

    2 is also a factor of 12:)

    Reply
  73. MrsH7285 . says

    February 1, 2015 at 7:13 pm

    Thank you! I’d forgotten all about these from school so helped with
    daughters homework

    Reply
  74. Luke Clash says

    January 31, 2015 at 11:08 am

    Doesn’t 9 go in to 45? 😛

    Reply
  75. salem elshahomi says

    January 23, 2015 at 7:49 pm

    thank you Mr.Deacon

    Reply
  76. salem elshahomi says

    January 23, 2015 at 7:48 pm

    thank you so much this has helped in a phenomenal way now I could go to
    class without being shouted at your a miracle

    Reply
  77. Kronite says

    January 23, 2015 at 4:23 am

    This ain’t no minecraft. Wtf.

    Reply
  78. Bhoutik Kaneriya says

    January 21, 2015 at 6:49 pm

    sir can you pls also help us out in solving quadratic equation…it’ll be
    really helpful to us..thankz in advance..:)

    Reply
  79. Bhoutik Kaneriya says

    January 21, 2015 at 6:46 pm

    thank u so much sir..:)

    Reply
  80. woto thegreat says

    January 21, 2015 at 6:06 am

    this helped so much thank you

    Reply
  81. Arjun vasanthan says

    January 20, 2015 at 5:41 pm

    Thanks this really helps I have a test tomorrow and this will really
    help

    Reply
  82. Ben Noble says

    January 19, 2015 at 6:09 pm

    oops a lot

    Reply
  83. Ben Noble says

    January 19, 2015 at 6:09 pm

    very useful thank you so very much you have helped me alot

    Reply
  84. Chantelle Luu says

    January 19, 2015 at 4:47 am

    Omg, Thanks so much!
    Now I finally get it!
    On my worksheet there weren’t any diagrams, this helped heaps!

    Reply
  85. محمد علاء says

    January 17, 2015 at 8:35 am

    Thank you 2 much
    Now I can do any HCF activities

    Reply
  86. Nicole Huffman Hollins says

    January 16, 2015 at 7:07 am

    Great video. I homeschool my son. We are doing fractions. This was very
    helpful. Thank you.

    Reply
  87. Moon Light 101 says

    January 14, 2015 at 9:22 am

    You left out 2 as a factor for 12

    Reply
  88. Suryaa Kumara Relan says

    January 14, 2015 at 1:04 am

    I can not thank you enough for this video !!! It helped me save alot of
    time on my GRE. Thanks alot !!!

    Reply
  89. MrFudgestick says

    January 8, 2015 at 9:17 pm

    you have a very punchable face +Simon Deacon

    Reply
  90. Heather Brown says

    January 7, 2015 at 9:05 am

    Reply
  91. Meghan Lohse says

    January 5, 2015 at 8:34 am

    Yay! This helped me study for a big test! I hope I get good marks

    Reply
  92. Sean Roche says

    December 13, 2014 at 6:58 pm

    f~u~c~k U

    Reply
  93. Shaan Niazi says

    December 13, 2014 at 4:05 pm

    ur the best

    Reply
  94. Shaan Niazi says

    December 13, 2014 at 4:00 pm

    how is it 2x2x3 dont get it

    Reply
  95. Fran Padavic says

    December 10, 2014 at 5:34 pm

    I was looking for Shotbow HCF!

    Reply
  96. COD Gaming says

    December 9, 2014 at 5:01 pm

    Thanks!

    Reply
  97. Maxim Lanez says

    December 8, 2014 at 12:01 pm

    thanks mate needed to refresh my memory

    Reply
  98. Bassam alnasser says

    December 5, 2014 at 11:56 pm

    Thank you so much! very helpful

    Reply
  99. Leo Lorente says

    December 4, 2014 at 7:10 am

    Thank you so much if you hadn’t helped me I wouldn’t have passed my test!!!

    Reply
  100. antoinette tesecum says

    December 3, 2014 at 1:07 am

    could u plz teach how to work out a velocity time graph

    Reply
  101. Arslan Dar says

    November 30, 2014 at 11:08 pm

    You helped me do my home work thanks 😀

    Reply
  102. Rambo Skullcrusher says

    November 25, 2014 at 6:38 pm

    Thank you I wish you were my teacher

    Reply
  103. Rachie Kimberly says

    November 23, 2014 at 6:36 pm

    thank you so much ,this has helped me a lot with revision

    Reply
  104. Rachie Kimberly says

    November 23, 2014 at 6:28 pm

    thank you so much this is a lot easier than my maths teachers made it out
    to be

    Reply
  105. mckaeda Augustine says

    November 22, 2014 at 9:39 pm

    thank you sooo much. my memory kinda ran dry, and i forgot how to do this

    Reply
  106. Amy Lieu says

    November 18, 2014 at 7:18 pm

    hi Simon Deacon thank you it helped me at my maths homework 🙂

    Reply
  107. GokuTheMc saiyan says

    November 12, 2014 at 7:57 am

    u are da man……man
    thanks

    Reply
  108. Sidkenie Toulon says

    November 9, 2014 at 10:28 pm

    thanks for the info but how do you solve the hcf with three numbers like
    3,12 , 24

    Reply
  109. Mike L says

    November 6, 2014 at 3:02 am

    GREAT GUY, GREAT METHOD!

    Reply
  110. Melissa Riches says

    November 4, 2014 at 10:14 pm

    Why did you only use one set of threes though?? Because there was two
    threes left and a two??v

    Reply
  111. Turlough Farnan says

    November 4, 2014 at 8:40 pm

    very useful like your videos you should make one on area of circles and
    circumference

    Reply
  112. Fahad Alajmi says

    November 4, 2014 at 6:47 pm

    Thank you sir we appreciate your hard work .

    Reply
  113. sidsood98 says

    November 2, 2014 at 6:22 pm

    night before exam revision and you really helped out thanks soooo much

    Reply
  114. Sadia elsheikh says

    October 23, 2014 at 9:43 pm

    what if there was 2 common multiple? are we gonna add them or something? 😮

    Reply
  115. fanoflots099 says

    October 21, 2014 at 9:56 pm

    Thanks so much for this..It’s gonna be helpful for my test tomoz

    Reply
  116. wetman king says

    October 21, 2014 at 2:18 am

    Thx

    Reply
  117. Shush Ninja says

    October 16, 2014 at 11:04 pm

    why do u have to talk so much at the start?

    Reply
  118. Shush Ninja says

    October 16, 2014 at 11:02 pm

    how can you forget 2?

    Reply
  119. Battlefield Gamer says

    October 15, 2014 at 2:33 pm

    THANK YOU SIR, I WAS WORRIED ABOUT NOT KNOWING THIS.

    Reply
  120. YGT TGY says

    October 13, 2014 at 5:27 pm

    Oh my god this is so much better and faster than the method my math teacher
    showed me! Thanks a lot Sir. 🙂

    Reply
  121. dom sherry says

    October 12, 2014 at 4:09 pm

    Really helpful for test thanks

    Reply
  122. Talvinder Singh says

    October 11, 2014 at 8:23 am

    8 and 12 =24 and 48

    Reply
  123. Kevin Amanor says

    October 7, 2014 at 8:12 pm

    3:00

    Reply
  124. Kevin Amanor says

    October 7, 2014 at 8:11 pm

    Dude, 2 can go into 12!, you forgot to add two to the list

    Reply
  125. Lucy Larner says

    October 6, 2014 at 8:18 pm

    You are amazing! Thanks so much I asked my friend to help me and she
    confused me so much this is clear and easy to understand 100% recommending
    to my friends

    Reply
  126. Gloria oteng says

    October 5, 2014 at 8:43 pm

    THNK YOU SOO MUCH- my maths teacher is really bad so i dnt understand wat
    she’s saying neither does the class so this vid really helped whilst doing
    my homework

    Reply
  127. gangasta syam says

    October 5, 2014 at 7:52 pm

    Thanks for the method 😀

    Reply
  128. Joshua Long says

    October 5, 2014 at 9:27 am

    That was really helpful.

    Reply
  129. Yohanna miji says

    October 1, 2014 at 11:18 pm

    thanks ….give me a solution. how to solve a algebra for class 10.

    Reply
  130. Guy that watches videos Youtube says

    September 30, 2014 at 6:53 pm

    Thanks! Homework done and dusted

    Reply
  131. ProBro Bros123 says

    September 29, 2014 at 5:01 pm

    That was very useful because I was struggling with the LCM method for
    homework thanks a lot+ Learn your 8 times tables 😀

    Reply
  132. giovanni rubeo says

    September 25, 2014 at 1:26 am

    thanks bro

    Reply
  133. Akilah Lashley says

    September 24, 2014 at 2:18 am

    Finished my maths homework…thanks!!

    Reply
  134. Alhaji Barrie says

    September 23, 2014 at 4:56 pm

    Thanks

    Reply
  135. Uddham Singh says

    September 22, 2014 at 7:26 pm

    Thanks I had maths homework favourite subject and at the time I was
    confused thanks once again

    Reply
  136. lujein Aldarooty says

    September 20, 2014 at 12:44 pm

    Thank u Mr Simon u really helped

    Reply
  137. Ezzy Ses says

    September 17, 2014 at 8:11 pm

    Thank you! I’m in year seven though what should I do if there is two same
    numbers in both time tables?

    Reply
  138. Alpsok says

    September 14, 2014 at 8:00 pm

    Mr Deacon, this is brilliant
    Thank you so much
    Your tone and delivery method is great.

    Reply
  139. Felicia King says

    September 14, 2014 at 8:52 am

    Thanks much

    Reply
  140. SeriouslyFunnyNot says

    September 13, 2014 at 3:32 pm

    Thanks a lot!

    Reply
  141. ethan ponnudurai says

    September 11, 2014 at 10:59 am

    on*

    Reply
  142. ethan ponnudurai says

    September 11, 2014 at 10:59 am

    do u hav a vid in prime decomposition?

    Reply
  143. fanoflots099 says

    September 10, 2014 at 8:36 pm

    Thanks so much! It’s really easy to understand and you explain better than
    my teachers lol ^_^

    Reply
  144. DeeWeext says

    September 10, 2014 at 10:57 am

    What button.. Whaaaaaat button!?

    Reply
  145. Edward Hope says

    September 9, 2014 at 8:28 pm

    thanks!

    Reply
  146. Alpha kenny body says

    September 9, 2014 at 6:16 pm

    but i don’t understand why u multiplied 2 2 3 not 2 3 3

    Reply
  147. Marcus Holba says

    September 9, 2014 at 5:31 pm

    Cheers really easy to understand

    Reply
  148. ethan ponnudurai says

    September 8, 2014 at 1:24 pm

    OMG thanks for helping me! I did not understand anything from my textbook
    🙂

    Reply
  149. Flora Ferroni says

    September 8, 2014 at 10:15 am

    Tahnkyou 😀 you helped me a lot 😀 keep up the good work

    Reply
  150. Mia Bromilow says

    September 6, 2014 at 3:21 pm

    I am studying highest common factors for GCSEs in school at the moment, and
    this video really helped me, so thanks! 🙂

    Reply
  151. Laurent Brutsch says

    September 1, 2014 at 10:03 am

    THANK YOU!

    HACKS!

    Reply
  152. kolinio musuka says

    August 28, 2014 at 5:54 am

    thanks great tutor

    Reply
  153. Rainy tp says

    August 20, 2014 at 10:14 am

    Thank you. Now I will teach my son a lesson 😉

    Reply
  154. taryn wiggins says

    August 19, 2014 at 5:33 pm

    This is brilliant I tell you, coming from someone who is horrible at math.
    Thank you and THANK YOU

    Reply
  155. fabiapreece says

    July 28, 2014 at 12:05 pm

    Just found your channel, and this makes sense to me 😀 Thank you.

    Reply
  156. Rajni Jain says

    July 26, 2014 at 3:26 pm

    it was very useful…thanks !

    Reply
  157. pranay kapoor says

    July 24, 2014 at 9:20 am

    thanks a lot 🙂

    Reply
  158. Gaby Thompson says

    July 23, 2014 at 11:10 am

    This is really cool but im trying to divide bigger numbers like 245 and 90
    etc. :p

    Reply
  159. 1703Bay says

    July 17, 2014 at 10:41 pm

    You really suck you left out 2

    Reply
  160. dheveen ratnayake says

    July 3, 2014 at 12:53 pm

    thx so much, this really helped 🙂

    Reply
  161. terishma kaur says

    July 2, 2014 at 3:48 pm

    OMG thank you so much ..Literally hate maths and am so bad in maths lol but
    yh got exam in November and this has helped me 🙂

    Reply
  162. Ross Albany Ward says

    June 24, 2014 at 5:32 pm

    Thanks this really helped me I have been watching LOADS of your videos and
    love them all, easy, clear and great methods. Don’t worry about your 8
    times table, you will learn them soon enough. hehe :-).

    Reply
  163. Harvie Gasendo says

    June 22, 2014 at 8:28 am

    your a lifesaver simon..thank you very much ..because of you and my
    hardwork i passed my algebra lessons ty very much 🙂

    Reply
  164. Tizzy Mariah says

    June 21, 2014 at 12:29 am

    omg!!! my hero 🙂

    Reply
  165. Tizzy Mariah says

    June 21, 2014 at 12:23 am

    thx alott you really help me!!

    Reply
  166. Tizzy Mariah says

    June 21, 2014 at 12:22 am

    wow!.thats very quick.

    Reply
  167. Kashkuda Kashiri says

    June 13, 2014 at 2:10 am

    been across your channel a couple of times :D, got my final maths exam
    today !, its 2AM this has really helped me; wish i started working this
    hard earlier 🙁 in school- thank you so much anyways hoping for a C

    Reply
  168. Mansurkhon Kayumov says

    June 11, 2014 at 8:58 pm

    You are really helping ps im in year 7 ive missed a lot in school so big
    thanks for help

    Reply
  169. Annabel Wright says

    June 8, 2014 at 5:09 pm

    Thank you for the video, LCM HCM and Primes have been a struggle all year.
    your videos are amazing!

    Reply
  170. Annabel Wright says

    June 8, 2014 at 5:02 pm

    Really silly but does 2 not go into 12 also? Videos are great wish I knew
    about them when I started my course. My exam is tomorrow and only found you
    yesterday!!!

    Reply
  171. Josh haffazi says

    June 8, 2014 at 3:55 pm

    this video really helped thank you!!!!! 🙂

    Reply
  172. tunde salawu says

    June 7, 2014 at 7:31 pm

    the sum is not correct

    Reply
  173. Rachel Ainslie says

    June 4, 2014 at 7:46 pm

    u missed out two…

    Reply
  174. stephen barker says

    June 4, 2014 at 4:19 pm

    can you tell me how to do factorising

    Reply
  175. Casper Bman says

    June 2, 2014 at 8:32 pm

    +Luker Stormrage

    Reply
  176. hadi farrukh says

    June 1, 2014 at 3:31 am

    I might do really well in my end of year test courtesy of you and your
    great video… Thank you very much!!!

    Reply
  177. Casper Bman says

    May 31, 2014 at 11:08 am

    Day has been saved

    Reply
  178. Casper Bman says

    May 31, 2014 at 11:08 am

    Saved the day mate

    Reply
  179. SuperMsThe says

    May 9, 2014 at 7:16 pm

    u missed a 2 on the factors of 12 its meant to be1,2,3,4,6 and 12

    Reply
  180. Fhd says

    May 9, 2014 at 4:02 pm

    Thanks alot for helping appreciate it

    Reply
  181. Saeed Amir says

    May 5, 2014 at 8:41 pm

    u just made my confiused path easier TTHANKS ALOTTTTTT…….

    Reply
  182. Ashley So says

    April 29, 2014 at 10:51 am

    Thank you very much !! You can help me to do my math homework (:

    Reply
  183. Rishi Ram Gautam says

    April 23, 2014 at 2:23 am

    Thank you so much for excellent video. I forgot this method which i’d
    learnt 20 years before in my school days. Today i found this while
    searching for HCF method to guide my daughter. Thanks a lot.

    Reply
  184. Ams amriys says

    April 16, 2014 at 11:20 am

    Brilliant

    Reply
  185. buggaman2009 says

    April 5, 2014 at 7:57 am

    for 12 times 9 times 2 u wrote 12*9 = 2 at 3:50 😀

    Reply
  186. buggaman2009 says

    April 5, 2014 at 6:57 am

    This is not easy

    Reply
  187. Arthanen Redith says

    March 25, 2014 at 9:04 am

    Thanks

    Reply
  188. Arthanen Redith says

    March 25, 2014 at 9:03 am

    Hi

    Reply
  189. RoflJoker1994 says

    February 28, 2014 at 2:56 am

    can u just get to the point ? fucking dumb cunt wasting my time

    Reply
  190. Antonino Mineo says

    February 17, 2014 at 9:12 pm

    A very well done sr. I have watched similar video in Italian language as
    I’m italian and they were not as clear as your.

    Reply
  191. TheLabUnit | Planning says

    February 10, 2014 at 8:36 pm

    you missed out 2 though on the 12 line why?

    Reply
  192. Agam Singh Gujral says

    January 30, 2014 at 5:54 pm

    0:54 is the way to go 🙂
    save time

    Reply
  193. ruth samuel says

    January 29, 2014 at 6:27 pm

    Please say it is not so. Not the last lesson nooooo!

    Reply
  194. ruth samuel says

    January 29, 2014 at 6:05 pm

    This was very helpful. (Thanks for using youtube educational)

    Reply
  195. Muntasir Yussuf says

    January 6, 2014 at 6:35 pm

    9 is a factor of 45

    Reply
  196. Peter Close says

    December 31, 2013 at 1:37 am

    Thank you huge help, I get 3D trig, quadratics and all the “outside the
    box” hard stuff but its the simple things I always run back too haha,
    thanks again

    Reply
  197. Hamza Iftikher says

    December 10, 2013 at 9:06 pm

    Joking I seriously did good thanks!!!

    Reply
  198. Hamza Iftikher says

    December 10, 2013 at 9:05 pm

    Not good got a b in mock exam

    Reply
  199. Rebecca Jackson says

    December 9, 2013 at 8:59 pm

    Thankyou very much your very helpful it was very easy to understand!

    Reply
  200. Simon Deacon says

    December 8, 2013 at 10:41 am

    Please like and leave a comment!

    Visit https://www.3minutemaths.co.uk for real maths, tips and techniques.

    Reply
  201. Simon Deacon says

    December 8, 2013 at 10:41 am

    Please like and leave a comment!

    Visit https://www.3minutemaths.co.uk for real maths, tips and techniques.

    Reply
  202. Danny Fisher says

    November 22, 2013 at 6:33 pm

    Isn’t it 3 min maths

    Reply
  203. Danny Fisher says

    November 22, 2013 at 6:33 pm

    Thank you I really enjoyed this

    Reply
  204. Oliver Beck says

    November 16, 2013 at 10:02 am

    2 is A factor of 12

    Reply
  205. Umar Raja says

    November 13, 2013 at 5:57 pm

    you are awesome in maths but lol forgetting ur 8 times table

    Reply
  206. Umar Raja says

    November 13, 2013 at 5:50 pm

    thanks it helped me alot thx vry much

    Reply
  207. Riley Soares says

    November 13, 2013 at 9:23 am

    Thank you so much! You saved a lot of my time! Amazing! What are the other
    methods of finding the LCM and HCF? What are their different pros and cons?

    Reply
  208. XxPNH207xX says

    November 6, 2013 at 6:27 pm

    You’re method is very clear and extremely simple to understand even better
    than my maths teacher!

    Reply
  209. desmond micah says

    November 6, 2013 at 12:01 am

    i would like to be in your lessons

    Reply
  210. Simon Deacon says

    October 27, 2013 at 11:59 pm

    Please post, pin, tweet, like or subscribe!

    Reply
  211. Simon Deacon says

    October 27, 2013 at 11:59 pm

    Please post, pin, tweet, like or subscribe!

    Reply
  212. Simon Deacon says

    October 27, 2013 at 11:57 pm

    Please post, pin, tweet, like or subscribe!

    Reply
  213. Simon Deacon says

    October 27, 2013 at 11:57 pm

    Please post, pin, tweet, like or subscribe!

    Reply
  214. TheImMajestic says

    October 27, 2013 at 5:07 pm

    Thank you very much!

    Reply
  215. Charlotte Woods says

    October 25, 2013 at 8:00 pm

    thank you really helpful

    Reply
  216. Simon Deacon says

    October 25, 2013 at 9:11 am

    Brilliant – congrats!

    Reply
  217. Memoriesof syria syria says

    October 24, 2013 at 10:09 pm

    Thanx i passed the exam 😀 Thank thank youuuuuuuu

    Reply
  218. Simon Deacon says

    October 21, 2013 at 9:58 pm

    Hi try ‘How to work out HCF and LCM using factor trees’ on the channel – might help? All best S

    Reply
  219. tatiana lisseth says

    October 21, 2013 at 9:05 pm

    My maths teach also told me somethibg about that u have to add the numbers. Ex: hfc:12 & 14 i have use the tree methodso i got 12: 6×2,2×3 ;14: 7×2. So rhe LCM is 2x2x3x6x7=504 i just dont really understand that

    Reply
  220. Simon Deacon says

    October 18, 2013 at 12:54 pm

    That’s great and glad it helped 🙂

    Reply
  221. sweetshabine69 says

    October 17, 2013 at 6:50 am

    u made my life so much easier

    Reply
  222. Simon Deacon says

    October 9, 2013 at 11:40 am

    Hi Billy – that’s great – congratulations!

    Reply
  223. Billy Jones says

    October 8, 2013 at 7:48 pm

    I love you! I am in year 8 and got an 8a in my test, so happy all thanks to you!

    Reply
  224. Simon Deacon says

    October 6, 2013 at 9:59 pm

    Hi – yes, 7 is the HCF of 21 and 35. All best S

    Reply
  225. Simon Deacon says

    October 6, 2013 at 9:58 pm

    Hi – yes, the factors of 16 are 1,2,4,8 and 16. Rgds S

    Reply
  226. Simon Deacon says

    October 6, 2013 at 9:57 pm

    ooops 🙂

    Reply
  227. Nimmie Shakes says

    October 6, 2013 at 5:52 pm

    hi thank you soo much u helped me alot and can ask tht hcf of 21 and 35 is 7??? 🙂

    Reply
  228. Blackeyepanda BP says

    October 6, 2013 at 4:02 pm

    Would 16 be 1,2,4,8,16?

    Reply
  229. samiya chaudhury says

    October 4, 2013 at 11:08 pm

    you didn’t put 2 for 8&12 question.

    Reply
  230. Dav Dan says

    September 29, 2013 at 5:44 pm

    Thanks so much!

    Reply
  231. Timi Awolaja says

    September 21, 2013 at 6:50 pm

    Very helpful ! Thank you Simon

    Reply
  232. Simon Deacon says

    September 21, 2013 at 11:08 am

    HI Ivan – yes it will although might get a little complex when you write all the factors at the end. You could also try How to work out HCF and LCM using short division on the channel.
    I hope this helps and thanks for the comment.

    All best

    S

    Reply
  233. Ivan Loner says

    September 21, 2013 at 8:21 am

    Will it work for 4 numbers?

    Reply
  234. Ivan Loner says

    September 21, 2013 at 7:58 am

    I like how your attitude to all your viewers are always positive

    Reply
  235. Eula Gibson says

    September 17, 2013 at 4:53 am

    Thank you quite helpful

    Reply
  236. Frodo Baggins says

    September 4, 2013 at 7:27 pm

    Thank you! It Helped me sooo much 🙂 the teacher did not explain it too well and now i understand!!

    Reply
  237. Никита Богданов says

    August 30, 2013 at 9:15 pm

    we learn that in 2nd or 3 class in school =) lol

    Reply
  238. Simon Deacon says

    August 20, 2013 at 3:01 pm

    Hi – best advice is to try to divide by “2 or 3 or 5 or something else.” The numbers aren’t always so neat but with 75 and 120 try
    5 first (will give 15 and 24)
    then
    3 (will give 5 and 8, which will be the bottom numbers)
    So HCF is 15 and LCM is 600.
    I hope this helps. Rgds S

    Reply
  239. Simon Deacon says

    August 20, 2013 at 2:53 pm

    Hi – yes, The prime factors of 108 are along the left and then the number at the bottom. You might need to convert this (9 is 3 x 3). So 108 as the sum of its prime factors is:
    108 = 2 x 2 x 3 x (3 x 3)

    The brackets is 9 from the bottom.

    I hope this helps and thanks for the comment. All best S

    Reply
  240. James Abiola says

    August 20, 2013 at 2:10 pm

    Can you also work out the prime factors using short division (bus stop method) or is it just Hcfs and Lcms?

    Reply
  241. James Abiola says

    August 20, 2013 at 1:51 pm

    what if it only goes into it once! e.g Hcf&Lcm of 75 and 120! -_-

    Reply
  242. Simon Deacon says

    August 18, 2013 at 11:07 pm

    Hi – yes it will – but it’s a really hard question!

    Reply
  243. Simon Deacon says

    August 18, 2013 at 11:06 pm

    Hi – Thanks for the comment. You English is much better than my Indonesian! All best S

    Reply
  244. Park Ri Seul says

    August 18, 2013 at 2:49 pm

    It really save me!
    My teacher make exercise about finding HCF and LCM with factor trees.
    Since I always use the quickest way to find HCF and LCM (my teacher in grade 6 teach my class so we will do UN faster), I never try using factor trees again and forget how to count it. You help me a lot!

    Thank you 🙂
    I’m sorry for my bad english, I’m still learning.
    I’m from Indonesia 🙂

    Reply
  245. Park Ri Seul says

    August 18, 2013 at 2:34 pm

    Did it works on 14175 and 101871 ?

    Reply
  246. Habiba Ahmed says

    July 17, 2013 at 6:48 pm

    helped a lot thanks! 🙂 xx

    Reply
  247. Emily xo says

    June 18, 2013 at 10:32 pm

    thank you so much! really helped!

    Reply
  248. John-Paul Fitzgerald says

    June 12, 2013 at 9:18 pm

    Genius it’s so much simpler now lol

    Reply
  249. Lamborghini968 says

    June 10, 2013 at 9:27 pm

    Thanks!!!!!!!!!

    Reply
  250. Simon Deacon says

    June 10, 2013 at 9:03 pm

    Good luck!

    Reply
  251. Lamborghini968 says

    June 10, 2013 at 8:59 pm

    My Maths exam is tomorrow and hopefully I’ll pass!

    Reply
  252. KING Samurie says

    June 10, 2013 at 10:49 am

    this is the exact numbers that i have in my mid year exam

    Reply
  253. Simon Deacon says

    June 5, 2013 at 8:49 pm

    No prob – good luck with your test 🙂

    Reply
  254. Simon Deacon says

    June 5, 2013 at 8:49 pm

    No prob – good luck with your test 🙂

    Reply
  255. e shahid says

    June 5, 2013 at 8:37 pm

    thanks really helped for maths test tomorrow ;D

    Reply
  256. Lollet-Oliv Spano says

    May 22, 2013 at 6:51 am

    yes i also thank you alot because this is for sure going to be in my end of year exam

    Reply
  257. Joseph Maybin says

    May 19, 2013 at 9:29 pm

    Thanks helped me a lot 🙂

    Reply
  258. Eumesh Weerapura says

    May 8, 2013 at 12:24 am

    Its very helpful. Thank you sir.

    Reply
  259. Simon Deacon says

    May 6, 2013 at 11:20 pm

    Hi – there’s a few in the playlist on the channel. I’ve posted one as a video response for you to link through from. Hope they help and all best S

    Reply
  260. Daniel Donegan says

    May 6, 2013 at 9:52 pm

    Can u make a video on factoring

    Reply
  261. scaddan98 says

    April 28, 2013 at 4:50 pm

    Thank you! This really helped me understand it for my end of year test in a couple of weeks!

    Reply
  262. Simon Deacon says

    April 26, 2013 at 3:15 pm

    That’s great – glad it helped 🙂

    Reply
  263. Sushma senthil kumar says

    April 26, 2013 at 2:40 pm

    Thanks a lot…. 🙂 very helpful!

    Reply
  264. Simon Deacon says

    April 16, 2013 at 12:06 pm

    oops ! Thanks for letting me know 🙂

    Reply
  265. Basil Shurrab says

    April 15, 2013 at 3:41 pm

    Thank u
    Ps.in the minute 3.43 u placed an equal sign not a multiplication sign

    Reply
  266. Simon Deacon says

    March 6, 2013 at 11:34 am

    Hi – thanks for question. Yes, it works with 3 or more numbers. It can also be used with algebraic equations.

    Reply
  267. fabulachic017 says

    March 6, 2013 at 4:33 am

    Does this work with 3 numbers?

    Reply
  268. usmaanmalik4 says

    February 5, 2013 at 8:57 pm

    Thanks got a maths test tomorrow / please hope it goes well

    Reply
  269. Ayuub Nur says

    January 28, 2013 at 8:57 pm

    This Helped so much easier way then i learnt thanks :D.

    Reply
  270. Jess Rowley says

    October 11, 2012 at 9:12 pm

    omg! This was the exact same numbers and question on my homework!

    Reply
  271. Rishad Jubin says

    September 27, 2012 at 8:19 pm

    thank you so much……:)

    Reply
  272. Sam Hannon says

    September 25, 2012 at 8:25 pm

    thumbs up if u have a maths test tomorrow

    Reply
  273. ciko963 says

    September 22, 2012 at 6:36 am

    This is very helpful. Thanks!

    Reply
  274. Labake Salau says

    September 16, 2012 at 2:24 pm

    Thank you so much

    Reply
  275. xLogicify says

    September 13, 2012 at 6:55 am

    You*

    Reply
  276. xLogicify says

    September 13, 2012 at 6:55 am

    This really helped, thank yoi sir.

    Reply
  277. Ayaz Jubaer says

    September 12, 2012 at 11:34 pm

    really helpful. thank you very much.

    Reply
  278. Simon Deacon says

    September 9, 2012 at 12:13 am

    Thanks – great observation. I will be reshooting this as the sound is poor quality. Kind Regards S

    Reply
  279. Ahmad Shafiqullah says

    September 8, 2012 at 10:14 pm

    Thanks but u put an equal sign rather than time sign at the bottom 3:41

    Reply
  280. Naqash Haider says

    June 27, 2012 at 9:08 am

    great vid..thanks a million….

    Reply
  281. RobloxReviewsTV1 says

    June 12, 2012 at 9:35 pm

    Damn I wish I saw this before my monday exam :/

    Reply
  282. Simon Deacon says

    June 10, 2012 at 11:35 pm

    Hi – thanks for comment – best of luck!

    Reply
  283. Simon Deacon says

    June 10, 2012 at 11:31 pm

    Great question!
    I’ve posted a video that uses short division to work out HCF – you could use this to find p. The method continues until you can’t use any more common factors to divide. Try putting 12 as the divisor, 24 as the first number with ‘p’ as the second.
    As you divide through you’ll get 2 underneath the 24. Underneath the p you need a number so that the 2 and this number can’t be divided anymore.
    If you use, say, 3 it would mean that p is 36.
    A 5 means p is 60.
    Hope this helps.

    Reply
  284. TheSimpleAdam says

    June 10, 2012 at 8:48 pm

    Got A GCSE grade c foundation paper :3 wish me look (: and this vid really helped! Thanks.

    Reply
  285. amsternaitor says

    June 9, 2012 at 11:43 pm

    @ImokaRo mate, i’ve got the same exam as you OCR unit 1? good luck mate

    Reply
  286. Simon Deacon says

    June 9, 2012 at 8:56 pm

    Thanks for your comment and good luck for Monday!

    Reply
  287. ImoKaRo says

    June 9, 2012 at 6:09 pm

    maths exam on monday and this really helped thanks 😀

    Reply
  288. QueenOfAmber says

    June 7, 2012 at 6:39 pm

    So HCF = numbers in common.
    LCM = all factors from each number multiplied together?
    Thanks for the video mate! 🙂

    Reply
  289. Gandalf Greyhame says

    May 29, 2012 at 2:02 pm

    Great tutorial! Thanks!

    Reply
  290. amir cortez says

    May 4, 2012 at 11:04 pm

    great tutorial !

    Reply
  291. mattguyman says

    April 3, 2012 at 12:22 pm

    Great vid really helped!

    Reply
  292. Victoria Jane says

    March 22, 2012 at 8:22 pm

    Thank-you 🙂

    Reply
  293. NoblenessDeee says

    March 2, 2012 at 12:15 pm

    Great Explanation. I Really loved it. Understood Perfectly.

    Reply

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