How to multiply using the partition method - KS3 Maths

Key points

The method of multiplication involves breaking numbers into parts. This method is useful in making a multiplication easier to manage. To use this method successfully you need to be able to:

break down (partition) a number using your understanding of place value
recall times-tables up to 9 x 9
multiply by multiples of powers of ten

Partition method of multiplication by a 1-digit number

Partition the number using the of each digit.
Multiply each of these numbers by the 1-digit number and align the answers to the right.
Add the to give the answer.

Example: calculate 4257 x 6

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Use the partition method to calculate 4257 × 6
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Partition 4000 into thousands, hundreds, tens and units.
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Multiply each place value by 6 and align the answers to the right.
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Add the products to give the answer to 4257 x 6. Write the answer 25,542 clearly.

Partition method of multiplication by a 2-digit number

Use the partition method to multiply a 3-digit number by a 2-digit number.

the smaller number using the place values of each digit. Eg, to work out 352 × 27 multiply 352 by 20 and multiply 352 by 7
Add the two answers.

Example: calculate 352 x 27

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Use the partition method to calculate 352 × 27
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Partition 27 into tens and units. 27 = 20 + 7
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Multiply 352 by 20 and 352 by 7
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Add the products to give the answer to 352 x 27. Write the answer 9,504 clearly.
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27 could also be partitioned as 10 + 10 + 7. Whichever way you partition, the outcome and answer will be the same.

Practise the partition method

Try this quiz to practise multiplication using the partition method. You might need a pen and paper to help with workings out.

Real-world maths

When you do not have a calculator, the partition method for multiplication is one way of calculating an answer. It is a skill used in many jobs such as builders, suppliers and flooring specialists. It is an invaluable skill for the world of work.

Newly built homes in a residential estate in England. — Image caption,
The partition method could be used to calculate the quantity of materials needed on a construction project.

A builder might use the partition method of multiplication to calculate the quantity of materials needed to build an entire housing estate.
A flooring specialist might use it to work out the area of flooring needed for a room when replacing carpets.