Box multiplying method. How to carry out box multiplication instead of short multiplication.

Box Multiplication Video

Box multiplication can be used instead of short multiplication to multiply large numbers by a single digit number. Box multiplication is easier to understand than short multiplication - although the method takes a little longer than short multiplication.

To begin with first you need to partition the large number, for example, 386 can be written as 300 + 60 + 8 or 97 can be written as 90 + 7. Write these partitioned numbers across the top of your box and put the single digit on the left hand side. Next multiply each of these partitioned numbers by the single digit number on the left hand side of the box. The numbers are easier to multiply if you cover up the zeros and add on the zeros back on, for example, to work out 700 × 3, do 7 × 3 which is 21 and add the two zeros on to give 2100. Finally, add up all your answers in your boxes to give you the final answer.

Example 1

Work out 68 × 4

Firstly, partition 68 into 60 and 8. Write these along the top of the box.

Next work out 60 × 4 = 240

And 8 × 4 = 32

Finally, add these together to give:

240 + 32 = 272

Example 2

Work out 713 × 6

Firstly, partition 713 into 700, 10 and 3. Write these along the top of the box.

Now multiply each of these partitioned numbers by 6:

700 × 6 = 4200

10 × 6 = 60

3 × 6 = 18

Finally, add up these three answers to give you final answer:

4200 + 60 + 18 = 4278

Example 3

Work out 2673 × 9

Firstly, partition 2673 into 2000, 600, 70 and 3. Write these along the top of the box.

Now multiply each of these partitioned numbers by 9:

2000 × 9 = 18000

600 × 9 = 5400

70 × 9 = 630

3 × 9 = 27

Finally, add up these three answers to give you final answer:

18000 + 5400 + 630 + 27 = 24057

Example 4

Work out 603 × 5

Firstly, partition 603 into 600 and 3. Since there are 0 tens then this box can be left out. Write these partitioned numbers along the top of the box.

Now multiply each of these partitioned numbers by 5:

600 × 5 = 3000

3 × 5 = 15

Finally, add up these three answers to give you final answer:

3000 + 15 = 3015

Box multiplication can also be used to multiply a large number by another large number (TU×TU or HTU × TU). Look back soon to learn how to do this.

More by this Author


No comments yet.

    0 of 8192 characters used
    Post Comment

    No HTML is allowed in comments, but URLs will be hyperlinked. Comments are not for promoting your articles or other sites.


    Click to Rate This Article
    working