MATHS TRICK #7

Maths Trick # 7 plays the multiplication of a number which is greater than 100 .

Example #1

                   625 X 11

Step 1 : Prefix a zero before the number given here... Then the  new number is    0 6 2 5

Step 2 : The unit digit of the number  should  be placed at the unit place of the product without any hesitation.
        
              0 6 2 5       X       11
           
                       5
Step 3 : Add up the unit and tens and the sum is placed at tens place


             0 6 2 5         X       11

                    75
 Step 4 : Add up the numbers  in the places tens and hundreds

              0 6 2 5       X         11

                 8 7 5
Step 5 :  Add up the places Hundreds and the already given zero

               0 6 2 5       X        11
                  
               6 8 7 5
               =====

Example # 2

                         5 4 2 1  X  1 1

Step 1 :            0 5 4 2 1
Step 2 :                        1
Step 3 :                     3 1       (2+1   = 3)
step 4  :                  6 3 1       (4+2   = 6)
Step 5 :               9 6 3 1       (5+4   = 9)        
Step 6 :            5 9 6 3 1       (0 + 5 = 5)

5421  X  11  =  59631
                         =====

Example #3

                  695 X 11

Step 1 :          0 6 9 5
Step 2 :                   5
Step 3 :                4 5  (9 + 5 = 14,   put 4  in the 10th place and the remainder 1 is added   to 100th place. Then the 100th place is 7 instead of 6)
Step 4 :             6  4 5    (7 + 9 = 16 . Put 6 in the 100th place and add the remainder 1 to 1000th place)
Step 5 :          7 6  4 5     (1 + 6 = 7)

695 X 11 = 7645

Example # 4

                      65321 X 11

                                             0   6   5   3    2  1
                                             7   1   8   5    3  1

Exercise
1. 5689 X 11       2.  7259 X 11

MATHS TRICK # 6

Maths Trick  # 6 plays the multiplication of a 2 digit number by 11

Example #1 : 
                      72 X 11
Step 1 : Separate the digits     --    7--2
Step 2 : Add up the digits       --   7 + 2 = 9
Step 3 :  Insert the sum between the separated digits .
             Then the product of 72 and 11 is   7 9 2 

Example # 2
                     95 X 11
Step 1 :   9--5
Step 2 :   9 + 5 = 14
Step 3 :   Here the sum of the digits  is greater than 9 . So the unit digit of the sum is inserted into the gap and Tens is added to the Tens place of the number.
                Then the result is  1045

 Maths can be fun

Example # 3

                      45 X 11

                     = 495
                       
Example # 4      
                        76 X 11
                                      = 836

Exercise : 

                1.  29X 11    2. 39 X 11     3. 62 X 11  (Calculation must be in the head)