The KS2 Long Multiplication Method – Made Easy for Primary Schoolers
Long Multiplication can be quite difficult for children in Year 5 and Year 6 to grasp, here at Think Academy UK, we have compiled some essential steps to help you guide your children to long multiplication success!
We have broken down the steps to success in 3 parts:
- What do you have to know about Long Multiplication?
- What your children should know about long multiplication already? (The pre-long multiplication basics)
- How to Explain Long Multiplication to your kids!
Page Contents
What is the Long Multiplication – What you (and your child) needs to know?
The National Curriculum details the basic learning requirements of long multiplication for children in Years 5&6:
“multiply numbers up to 4 digits by a one- or two-digit number using a formal written method, including long multiplication for two-digit numbers” (Year 5, NC)
“multiply multi-digit numbers up to 4 digits by a two-digit whole number using the formal written method of long multiplication” (Year 6, NC)
Typically, children will be introduced to the technique of long multiplication in Year 5 and this will be consolidated with calculations involving larger numbers in Year 6. This article will help you to condense the learnings across the 2 years in a single 10 minute read and help you to get your children to become long multiplication experts! No matter their year group!
The pre-long multiplication basics:
The process of learning itself is a lengthy one, to get to any end learning goal you need to start with the basics. Long multiplication is no different. The basics in our case is short multiplication and ensuring that your child is familiar with their times tables!
Being able to recall and remember the multiplication tables is essential in order for your child to be able to do long multiplication easily, as the method itself may seem difficult on the first approach – if your child has a strong foundation in their times tables, they will find long multiplication a lot easier!
If your child is not too familiar with their times tables, not to worry! Now is the perfect time to start. To help them to memorise their times tables easily, you can download a colourful times tables chart and work your way through them together.
Additional learning resources:
There are also a range of apps that you can use to support your child’s ability to do mental multiplication. Here are a few that we recommend at Think Academy:
https://apps.apple.com/gb/app/mental-math-cards-challenge/id500595081
Long multiplication practice is key!
Remember that practice is key! The key thing is to make sure that your child is practicing in short amounts and regularly to really engage those long-term memory muscles.
Once your child has a strong foundation in multiplication, the next step is to ensure that they understand short multiplication, an essential step for them to grasp the overall methodology!
Explaining short multiplication to your child:
- Start with a 2-digit number x 1-digit number
- Explain the method carefully:
First ensure that the units are aligned across both numbers:
First take the last column, times the bottom number by the top number, write your answer down below the line in the same column:
Then take the first column of the first number and times it by the second single digit number. Write your answer below:
For short multiplication, make sure to do a couple of examples if your child isn’t too confident, don’t forget to use examples that include carrying the 1!
Now, when your child is super comfortable with short multiplication, it is time to teach the long-awaited long multiplication method!
Teaching your child long multiplication
We use long multiplication when both numbers that we are multiplying by are either 2 digits or greater.
Let’s use the example of 12×43.
When the numbers have the same digits, we don’t need to worry about which one goes in the top row. When they are not, we put the number with the most amount of digits in the top row.
Like we did for short multiplication, the first step is to align the units of the two numbers in separate columns. Making sure that the smallest digit number is on the bottom.
Secondly, we need to times our single digit by the last digit of the number above, make sure to remember to carry your numbers if needed!
Then we do the same process for the next digit along our top number:
After we’ve multiplied all the digits in the top row by the last digit in the second row, we start the process again, this time with the next digit to the left in the bottom row. We write our answer now underneath our previous one and in the same column as the digit in the bottom row that we are multiplying by. We must remember to go back to the last column and add in a zero (as shown in the blue) since we are now working with a tens digit rather than a unit digit (40 instead of 3).
Now we repeat this, multiplying the same digit in the bottom row by the next digit to the left in the top row.
Once we have finished all the multiplication operations, we take the two numbers below the line in the previous picture, and add them together, make sure that they all stay in the right columns! This will give you the answer!
You can try this method with your child, using the same process and multiplying 2-digit numbers with 3+ digit numbers! Have a go!
Reviewing the Long Multiplication Method
There are a couple of types of long multiplication, so make sure you cover all forms, we recommend you teach your child in the following order:
- Long multiplication (two digits with two digits)
- Long multiplication (three digits with two digits)
- Long multiplication (4 digits with two digits)
Once your child gets familiar with the method and becomes more advanced you can also increase the numbers they are working with for example you can give an example that times’ a 5 digit number by a 3 digit number. Good Luck!
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