mathematics tricks and fun Lesson 1

Maths Tricks and Fun Lesson1

At the onset we will start with number 9. This number falls between number 8 and 10. It is an interesting number. Several names are attributed to it by mathematicians depending on its properties.   In

 nature several flowers , trees,shell of some snails all follow a pattern called fibonacci sequence. That is it increases in a pattern 1,1,2,3,5,8,13,21 like that.

 When you multiply 9 with any number, and when you

 add the digits of the product , the answer is 9, that is 

the digital sum is always 9 in a multiplication with 9. 

When you multiply 1 2 3 4 5 6 7 9 with 9 omitting 8 

the answer is always111111111. The same number

 when multiplied with 18, you get 222222222. Why because 9× 2 is 18.In the same way ,12345679 X 81

 will give you 999999999. While I was doing some multiplication with number 9, I saw some patterns 

arising and from that I have derived a code , which 

will enable us to find the square of a group o af 9, 3 

 and 6s

Now read carefully . This is the basis for the coming 

two or three classes .9 x 9 is 81, 9 X 11 x 99. So what

is 99 X 99 and the answer is 9801.999 X 999=998001 

in this way if  we   calculate , then we can get the 

answers for  big numbers,      avoiding the long

 calculation.

Let us start now . 99 X 99 = 9801. How did we get it 

so quickly. First count how many digits are there. 

2digits on the multiplicand side and 2 on the 

multiplier side. So totally 4 digits. For practice we 

will put 4 dots ie. Two dots small gap and two dots.

We will take one 9 each from the unit position of 

both sides and multiply . 9 x 9 is 81 so put 9 on the 

unit position dot of the multiplicand side and 1 on

 the unit position dot on the multiplier side . Here

 we

 have a special code to apply. It is One more One

 less.   one more than 8 is 9 so we'll put 9 beside 8 

on the multiplicand side and one less than one is 

zero so we will put zero beside one on the

 multiplier side.Thus th answer is 9801.There are

 other examples given. 999 X 999 = 998001 .

. What is the square of 9999. Here there are 8digits

totally. 4digit on the multiplicand side and 4 on the multiplier side. As taught earlier we will take 9 and

 9 x 9 is 81 we will put dots first , ( -  - - - - - - - -) 

The we will place 8 on the unit position dot on the multiplicand side and one on the multiplier side unit position. Then remaining three dots on the 

multiplicand side we will fill up with 9 since one 

morethan 8 is 9. Same way One less than 1 is zero.

So fill

 up 4 dots beside 1 in the multiplier side with zero. 

Thus the answer is 999 8 0001. this is easy and 

magical only if you remember the code.

Now I will show a little different calculation. Here the digits are not equal.eg 999× 99 .Here there are 3 

digits on the multiplicand side and 2 on the multiplier side..We will arrange the dots into 3 groups. Centre 

will be the extra 9s.on either side of it we will put 

dots for multiplicand side and multiplier side. So in

 this calculation one 9 is extra.We will put it in the 

middle and do the calculation as earlier .The answer 

is.  98 9 01.  

99999 x 999 here two extra 9s. So the answer is 

998 99 001. 

We will study multiplication of 33x 99 , 666 x 999, 

 444 x 999 etc in the classes to follow.