Wednesday, February 27, 2013

Trick to multiply three digit number with 11 verbally?

It is the extension of the trick that we done in last post  check it
It is easy to multiply three digit with 11 verbally.
Consider the number that we want to multiply with 11 For e.g. 123

123* 11 =           1353

                  123   
                        *11
                   1 3  5 3
    

The first digit from the right hand side will be the first digit of the number we are multiplying with 11

Here it  3 from 123

Second digit will be the sum of   the first two digit of the number here it is  3 + 2 = 5

Third digit  will be the sum of last two digit of the number here it is 2 + 1 = 3

last digit will be the last digit of the number here it  is 1

So answer is 1353

Note:- Add carry from all these addition to next number
Check this E.g.

Multiplication of number 999 by 11
      
          999
         × 11
      10 989 

first digit = 9
Second digit = 9+9 = 18 so the number is  8 carry 1
third  digit  =  9+9  18 plus the carry + 1 equal to 19
fourth digit = 9 + 1 equal to 10 

10989

Now calculate the value of  571×11, 589 ×11 and post  
your answer in comment.


Hope you like this.

Tuesday, February 26, 2013

Trick to multiply 2 digit number with 11 verbally

In this post i will show you how to multiply any two digit number with 11 verbally.
I am using term secondary number here for the number that we will multiply with 11
 In 11*11  11 is secondary number
      12*11  12 is secondary number
     13 * 11  13 is secondary number

11*11 = 121

 right most digit is the first number of the digit  your multiplying here it is 1
 middle digit is sum of  of both number you are multiplying with 11 is 1+1 = 2
last digit is  the one plus the carry if exist  from second number on from middle digit here it is  1
                                                      

11*13 = 143
            
 right most digit is the first number of the secondary number 3
middle digit is sum of  of both number you are multiplying with 11 is   (1+3)    4
last digit is  the one plus the carry on from middle digit here it is             1

11 * 14 = 154
right most digit is the first number secondary number here it is  4
middle digit is sum of  of secondary number   ( 4 + 1) = 5
last digit is  the one plus the carry if exist  from second number on from middle digit here it is 1

Lets try bigger number

11* 24
 right most digit is the first number secondary number 4
middle digit is sum of secondary number    ( 4 + 2) =6
last digit is  the one plus the carry if exist  from second number on from middle digit here it is 2

 so the answer is  264

11 * 89
right most digit is the first number secondary number9
middle digit is sum of secondary number    (8+9) = 17
ast digit is  the one plus the carry if exist  from second number on from middle digit here it is 8+1 = 9

answer is 979

Printfriendly

LinkWithin

Related Posts Plugin for WordPress, Blogger...