Mental Maths Shortcut 5 squared Genius

Here is a really quick way to square any number with a 5 on the end.

Lets take

Ok, so what you have to do is split up the numbers, giving you

and

Forget about the for the moment and do this:

Always add 1, adding 1 to the 4, so we get 4 + 1 = 5

Then multiply this answer, 5, by the original first number, 4

5 X 4 = 20

So what you have is 20 and

Everyone knows = 25 right? Well it does. This is what makes it easy.

Put the two answers together and that’s the answer!

2025

This works for any number ending in but when the numbers get over 100 it tends to get a little trickier with the multiplication.

Give it a try with another number.

Try , it isn’t difficult.

Split the numbers apart:

8 and

Again, forget about the

Add 1 to 8

8 + 1 = 9

Multiply 9 by the first number, which was 8

9 X 8 =72

Now, put all the numbers together, 72 and

= 25

So the answer is 7225

Try it out in a calculator once you have done it.

18 Responses to “Mental Maths Shortcut 5 squared Genius”

  1. i read some of them
    and i try to read rest of them later
    tanx
    it ’s so …
    i dont find a word which cab be suitable for the blanck
    but i think about it

    goodluck
    raha

  2. rsreenivasachar on June 23rd, 2007 at 11:18 am

    I have gone through quick squaring of two/three digit numbers.It is very funny and interesting. What about squaring of more than 4,5…n digits? Can anyone teach me in such a very simple way as to be understood by a lame man?
    Thanks
    rs

  3. Hey, I like the blog so far. I can’t seem to see the numbers. Somethine is missing?

  4. Okay for some reason I can see them now. Good work! Keep it up!

  5. it is a really useful technique. could it be used for 3 digit number as well square of 125

  6. This is truly simple. I love it. I look forward to more.

  7. Thanks Frankie, glad you like it.

  8. Mental math is a useful type of math using many simple operations. Nothing difficult as its written form. The purpose is to be able to handle computation mentally. The information in this post is clearly explained. Well-done!

    From: www.limeehai.com

  9. Squaring of numbers ending at 5 is amazing. I have tried with 2 digit, 3 digit and 4 digits (though it took some time without a calculator).Actually this is a general technique to multiply numbers with beginning digits same and the sum of the ending digits equal to 10.

    Take the numbers 24 and 26.
    Both numbers have the first digit same (2) and the sum of the last digits (4 + 6) equal to 10. Now apply the following formula to multiply these numbers.
    (2+1) * 2 | (4 * 6) => 6 | 24 = 624

    Squaring of numbers ending at 5 is an extension of this general formula.

  10. […] OConnor presents Mental Maths Shortcut 5 squared Genius | MemoryMentor’s Blog posted at MemoryMentor’s Blog. Kevin shows how easy it is to square numbers that end in […]

  11. Sivakumar Aloor on February 4th, 2008 at 11:15 am

    It is very simple and we don’t have to depend on calculator for squaring of numbers ending at 5. I expect more to see in future

    Well done. All Goodluck to you

    Sivakumar

  12. YOGANARAYANAN on May 7th, 2008 at 2:37 pm

    please tell me how to do squares of 3 digits
    Thanks

  13. YOGANARAYANAN on May 7th, 2008 at 2:38 pm

    it is amazing
    tell me how to do it for three digits squaring
    Thanks
    Yoganarayanan

  14. thank u

    for goving a wonderful collection in vadic maths
    tell me how to memorize a multiplication table
    amith

  15. good tricks in mathematics which will be very useful to students in their competitive examinations

  16. Squaring of numbers ending at 5 is amazing. Thanks for this . I am expecting more from you like this. Thanks a lot..

  17. its amazing sir,expecting more from u like this.thanks a lot

  18. thank u

    for goving a wonderful collection in vadic maths

    its amazing sir,expecting more from u like this.thanks a lot

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