3 X 3 Multiplication


3 X 3 Multiplication - Concepts
Class - 7th ISO Subjects
 
 
Concept Explanation
 

3 X 3 Multiplication

3 X  3 Multiplication : This is very fast method of multiplying a three digit number with a three digit number in a single line. It saves a lot of time in the various competitive exams where each second counts.

Suppose we want to multiply 265 with 132. We can perform this multiplication by following the steps given below:

Step 1: We have to multiply 265 and 132

Step 2: We will first multiply both the digits at the unit place i.e. 5 and 2.

This is called straight multiplication.

  5 X 2 = 10

Now unit place of the answer is 0

Carry is 1

Step 3: We will multiply the unit place digit of one number with the digit at tens place of the other number. That is we will multiply 5 with 3 and 2 with 6 and will then add. To the result we will add the carry if any.The unit place of the result is the tens place of the answer. If there is any carry it will be shifted to hundreds place.

This is multiplication in Cross.

Result = 3 X 5 + 2 X 6 + 1= 15 + 12+ 1= 28

Now the unit place of 28 i.e. 8 is the tens place in the answer and 2 is the carry for hundreds place.

Carry is 2

Step 4: We will multiply the unit place digit of one number with the digit at hundreds place of the other number. Also we will multiply the digits at tens place of both the number and will then add all these with carry if any. That is we will multiply 5 with 1 and 2 with 2. Further we will multiply 6 with 3  and will then add. To the result we will add the carry if any.The unit place of the result is the hundreds place of the answer. If there is any carry it will be shifted to thousands place.

This is multiplication in Double Cross.

Result = 5 X 1 + 2 X 2 + 6 X 3= 5 + 4 + 18= 27 + 2 = 29

Now the unit place of 29 i.e. 9 is the digit at the hundreds place in the answer and 2 is the carry for thousands place.

Carry is 2

Step 5: We will multiply the tens place digit of one number with the digit at hundreds place of the other number. That is we will multiply 6 with 1 and 2 with 3 and will then add. To the result we will add the carry if any.The unit place of the result is the thousands place of the answer. If there is any carry it will be shifted to ten thousands place.

This is multiplication in Cross.

Result = 6 X 1 + 2 X 3 + 2= 6 + 6+ 2= 14

Now the unit place of 14 i.e. 4 is the thousands place in the answer and 1 is the carry for the ten thousands place.

Carry is 1

Step 6: Now we will multiply both the digits at the hundreds place i.e. 1 and 2. and carry (if any) is added

This is called straight multiplication.

  1 X 2 + 1 = 3

Now this is written at the ten thousands place in the answer

So the answer = 34980

Illustration: Multiply 342 with 256

Step 1: We have to multiply 342 and 256

Step 2: We will first multiply both the digits at the unit place i.e. 2 and 6.

This is called straight multiplication.

  6 X 2 = 12

Now unit place of the answer is 2

Carry is 1

Step 3: We will multiply the unit place digit of one number with the digit at tens place of the other number. That is we will multiply 4 with 6 and 5 with 2 and will then add. To the result we will add the carry if any.The unit place of the result is the tens place of the answer. If there is any carry it will be shifted to hundreds place.

This is multiplication in Cross.

Result = 4 X 6 + 5 X 2 + 1= 24 + 10+ 1= 35

Now the unit place of 35 i.e. 5 is the tens place in the answer and 3 is the carry for hundreds place.Carry is 3

Step 4: We will multiply the unit place digit of one number with the digit at hundreds place of the other number. Also we will multiply the digits at tens place of both the number and will then add all these with carry if any. That is we will multiply 3 with 6 and 2 with 2. Further we will multiply 4 with 5  and will then add. To the result we will add the carry 3.The unit place of the result is the hundreds place of the answer. If there is any carry it will be shifted to thousands place.

This is multiplication in Double Cross.

Result = 3 X 6 + 2 X 2 + 4 X 5 + 3 = 18 + 4 + 20 + 3 = 42 + 3 = 45

Now the unit place of 45 i.e. 5 is the digit at the hundreds place in the answer and 4 is the carry for thousands place.

Carry is 4

Step 5: We will multiply the tens place digit of one number with the digit at hundreds place of the other number. That is we will multiply 3 with 5 and 4 with 2 and will then add. To the result we will add the carry if any.The unit place of the result is the thousands place of the answer. If there is any carry it will be shifted to ten thousands place.

This is multiplication in Cross.

Result = 3 X 5 + 4 X 2 + 4 = 15 + 8 + 4= 27

Now the unit place of 27 i.e. 7 is the thousands place in the answer and  2 is the carry for the ten thousands place.

Carry is 2

Step 6: Now we will multiply both the digits at the hundreds place i.e. 3 and 2. and carry (if any) is added

This is called straight multiplication.

  3 X 2 + 2 = 8

Now this is written at the ten thousands place in the answer

So the answer = 87552

 

 
 
 
 


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