Multiplication Trick for Fast multiplication

Multiplication Trick for Fast multiplication

Multiplication of two digit numbers

When the numbers being multiplied meet the following conditions

a)       Sum of the unit places of the numbers being multiplied is 10 and

b)      The numbers at the 10’s place are the same.

Example 1

19x11  - sum of the digits at the unit place = 9+1 =10 and numbers at the 10’s place are 1 in both.

Step 1 : multiply 9x1 = 09

Step 2:  multiply 1 with the next number which is 2 = 1x2=2

Step 3 : combine the numbers of Step 2 and 3 to get the answer

19x11 = 209

Example 2: 48x42

Step 1: multiply unit number digits 8x2=16

Step2 : multiply 4 with the next number  5  so 4x5 = 20

Step 3 combine both the answers and we have the answer 2016

Multiplication of 2 digit numbers – any digit

Example 18x24

Step 1: Write the numbers below each other as shown and then box the numbers on the left  hand side. Now multiply the numbers 2x1 =2

Step 2: Now multiply the numbers cross ways as shown and add it so we have 1x4=4 and 8x2=16 and then add it up so 16+4=20

Step 3: Box the left hand side numbers and multiply the same so we have 8x4 =32.

Now add it all together

 We keep 2 from 32 and add 3 to 20. Then we keep 3 and add 2 to the last number which is 2

 

So answer is 432

Multiplication of any 3 digit number

Example : 432x371

To do this multiplication remember the following pattern to find the answer 

We will use this pattern to solve any 3 digit  Number multiplication

Multiplication of any 3 digit number

Example : 432x371= 160272

Now lets solve this as per the above pattern 

We will first multiply the numbers at the unit place which is 2x1=2

We write 2 at the unit place

For the tens place we multiply criss cross which is 7x2=14

and 3x1=3

Then we will add both so we have 14+3= 17

We keep 7 from this at the 10’s place and take 1 as carryover

For the place at 100’s we multiply as shown in the figure units with 100’s place and tens with tens and then adding it up

So we have 4x1 =4, 2x3=6 and 3x7=21

So we have 4+6+21= 31

In this we add the number that we carried over which was 1 so we have 31+1=32

Keep 2 and carryover 3

Now for the next place we again have criss cross of 10’s and 100’s place numbers so we have 4x7=28 & 3x3=9  adding these

28+9 =37 and in this we add the carryover figure which is 3 so we have 37+3=40

We keep 0 and carryover 4

Now for the last part we multiply 4x3 and add the carryover which is 4 we get 16

Putting these values together we get the answer as 160272

you can create your own problems and solve .. this is very interesting and you can actually take this further and do 4 digit, 5 digit and 6 digit patterns...