Multiplication Techniques

Let me share to you multiplication techniques.

This involves a two-digit number!

1. How to multiply any two-digit number by 11?


Example: What is 23 x 11? 41 x 11? What about 97 x 11?

You want to know the technique?

Very Simple!

Just add the digits and insert the sum in the middle!

Very simple right?

Here's how it works...

23 x 11 => 2 + 3 = 5

Insert 5 in the middle of 2 and 3 so it will become -> 253!

What about 41 x 11?

41 x 11 => 4 + 1 = 5

Insert 5 in the middle of 4 and 5 so it will become -> 451!

Got it?

There's one problem....

How about if the sum exceeds 10? Just in the case of 97 x 11?

Simple... 9 + 7 = 16

So how can you insert 16 in the middle of 9 and 7?

Simple...

Insert 6 and 1 should be carried over to 9 just like addition...

So the last two digits of the answer is 67...

What happened to the 1 from the sum 16?

Add it to 9.

So then, 9+1 = 10

So there 10 is the first two digit of the answer!

And the last two digit is 67 as stated above...

So the answer is 1067!!!!

Isn't it amazing?


2. How to multiply any two-digit number ending in 5 by itself?

Sample: What is 25 x 25?

What about 95 x 95?

Simple...

Take the first digit of the number....

In the first example, that would be 2.

Add 1 to it. 2 + 1 = 3

And the multiply it to the original digit.

That would be 3 x 2 = 6

Lastly, affixed 25 as the last two-digits

Presto!

Answer is 625!!!


So can you now decipher how 95 x 95 became 9,025?

Isn't it amazing?

Simple Logic Problem

OOPPPSSS.... Don't scroll down too much!!!


What is:

(a-x) (b-x) (c-x) (d-x) ... (z-x) = ????

Please note that parentheses indicates multiplication.

Come on use your intuition!

Guess it first and before you view the answer below...



















KEPT THINKING????















ANSWER IS ZERO!!!!

WHY?





Beacause there will come a time for (x-x) which is of course ZERO.
And any number multiplied by zero is ZERO!!!


Isn't it amazing?

Magic Squares

One of the things that fascinated me was the so-called Magic Squares.

I did a self-study on this. Magic Squares are a set of numbers 1 to n squared, without repetition, that were placed in an n by n grid of square such that the sum of all the columns, rows, and diagonals were all the same and equivalent to a single number.

Please refer to this post to my other blog:

Fascinating Magic Squares

The Sum of 'N' Consecutive Numbers

How do you add:

1+ 2 + 3+ 4+ 5+ ... +100?

1+ 2+ 3+ 4+ 5+ ... + 1000?

You want a technique?

You might be smarter than a calculator!

Why not try this formula?

= n(n+1)/ 2

And so,

1+ 2 + 3+ 4+ 5+ ... +100 = 100(100+1)/2 = 5,050

1+ 2+ 3+ 4+ 5+ ... + 1000 = 1,000 (1,000+1)/2 = 500,500

1+ 2+ 3+ 4+ 5+ ... + 78 = 78 (78+1)/2 = 3,081

Isn't it math amazing?