Added: 5 years ago
From: smbotans
Views: 13,906
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  • The funny thing is, I needed to square 23 as well!

  • i do understand it but not with 15

  • @mathsquare

    when it comes to 15, it is a bit harder because of the carry you need to worry about ... using the method, you get 1 10 25 ... the carry of the 10 is 1 which you add to the first 1 to get 2 ... the carry of 25 is 2 which you add to the 0 to get 2 ... this gives you 1(1)0(2)5 which comes out as 225

  • crts?

  • i dont undrstand i really need help i got the crts

  • thanks.

    Im revising for christmas exams and this method just makes it far easier than writing out a sum and getting mixed up.

    But what if you have a three digit number?

    Make more videos please!!!!!!!!!!!!!!!!!! I could really use them!

    Are you a maths teacher????????????

    Bye thanks

    Signed: Br¦3g33N

  • i don't understand you dude

  • you dont understand the accent or the method?

  • Thank you!your methods are so simple and useful!

  • ÓóÓÓÓ

    O_O

    This was useful thanks!

  • Wat about 3 digit numbers like 345???

  • @LarrySergioZaratin do similar thing say your number is {abc} "a" is the digit in the hundreds column "b" is the digit in the tens column "c" is the digit in the ones column {abc} can be written as (100a+10b+c) therefore {abc}^2=(100a+10b+c)^2 =10000a^2+100b^2+c^2+2000ab+20­0ac+20bc =10000(a^2)+1000(2ab)+100(2ac+­b^2)+10(2bc)+1(c^2) =(a^2)||(2ab)||(2ac+b^2)||(2bc­)||(c^2) || signifies the next digit column. (eg 345=3||4||5)
  • This is basically a quadratic expansion! very simple!

  • this does not work for every number.. like 15..

  • Yes it does. You just have to think a little more. 15 X 15 = 225. 1 X 1 = 1(in the hundreds place) 5 X 5 = 25 (in the tens and ones place) 1 X 5 X 2 = 10 (Important! in the HUNDREDS and tens place). So you have 1 + 1 in the 'hundreds'; 2 + 0 in the 'tens'; and 5 in the 'ones'. 225. It sounds complicted written out but it's really easy once you think about it.

  • I wonder who wrote all the praises here... not only is that technique obscure, it fails to work for numbers such as 45, 67 or 89 where you get numbers bigger than 10 as a result of the multiplication. Sorry that I'm such a tightass but there are also semi-neat math tricks around. You'll be better off learning simply by heart that (a + b) squared = a squared + b squared + 2 a b.

  • It does work. I'll do 45 for you. 4X4=16, 5X5=25, and 4X5X2= 40. So you have 16, 25, and 40. The trick is to know slots the numbers go into, and the video illustrates it, but expects you to examine it. The answer is 2025, see if you can figure it out. Hint, 16+4=20

  • The principle used is just multiplying out brackets (handy though):

    13^2=(10+3)^2=10^2+10*3*2+3^2=­100+60+9=169.

  • Thank you! This is so fun!

  • WHAT!!! This is so much simpler than what we are taught in public school, in the states! Thank You!

  • This is the best way to do it!!! Better than that dood with dry erase board!!!!

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