06 Aug 2019

What Is The Lowest Common Multiple: Explained For Primary Parents And Kids

  • By Connor Whelan  | 
  • 06 Aug 2019  | 
  • 3 min read
  •  |  Free download

In this post we will be answering the question “what is the lowest common multiple?” and providing you with all of the information you need to help your child understand this area of maths. We’ve also got some questions based around the lowest common multiple that your child can complete, all to help them (and you) master maths fast!

What is a multiple in maths?

A multiple is a number that can be divided without any remainder. 

Sometimes it helps children to think of it as a number in another number’s times table – for example, 24 is a multiple of 12; it is also a multiple of 1, 2, 3, 4, 6, 8, and 24. The first five multiples of 6 are 6, 12, 18, 24 and 30.

Multiples and factors link together – for example, 4 is a factor of 12 and 12 is a multiple of 4.

What is a common multiple in maths?

A common multiple is a multiple that is shared by two or more numbers. 

12 is a common multiple of 6 and 4 as it’s in both the 6 and 4 times tables. 

Three common multiples of 6 and 9 are 18, 36 and 54.

What is the lowest common multiple?

The lowest common multiple is the lowest multiple shared by two or more numbers. 

For example, common multiples of 4 and 6 are 12, 24 and 36, but the lowest of those is 12; therefore, the lowest common multiple of 4 and 6 is 12. 

Primary Maths Dictionary For Parents & Kids

Download our FREE Maths Dictionary For Parents And Kids and find all of the KS2 maths words you'll ever need to know all in one convenient place!

How to find the lowest common multiple

One way of helping children to find the lowest common multiple is to ask them to list the multiples of each number until they come across the first one each number shares. 

For example, the LCM of 5 and 7 is 35:

what is the lowest common multiple - example


Does your child need help understanding lowest common multiples or other areas of KS2 maths?

Understanding what the lowest common multiple is can be tricky for children in KS2, but this is only one small area of primary maths! If your child needs more in-depth maths help to raise their attainment and confidence then take a closer look at Matr’s primary maths programmes.

We have different programmes designed for children in all primary year groups, so all that’s left for you to do is find the programme that matches your child’s needs, and then watch their confidence in maths blossom!


When will my child learn about lowest common multiples?

Children are introduced to multiples in Year 1 (perhaps without knowing the actual term) when they will count in multiples of twos, fives and tens. In Year 2, the non-statutory guidance suggests that children count in multiples of three to support their later understanding of a third.

In Year 3, children count from 0 in multiples of 4, 8, 50 and 100. The non-statutory guidance suggests that children use multiples of 2, 3, 4, 5, 8, 10, 50 and 100

In Year 4, children count in multiples of 6, 7, 9, 25 and 1000. The non-statutory guidance suggests that pupils use factors and multiples to recognise equivalent fractions and simplify where appropriate (for example, 6/9 = 2/3 or 1/4 = 2/8).

The National Curriculum states that Year 5 pupils should be taught to identify multiples and solve problems involving multiplication and division including using their knowledge of multiples.

Common multiples are not introduced until Year 6. Year 6 pupils are expected to use common multiples to express fractions in the same denomination and to solve problems involving unequal sharing and grouping using knowledge of fractions and multiples.

How do lowest common multiples relate to other areas of maths?

Lowest common multiples are useful when needing to express fractions in the same denomination (required when adding or subtracting, ordering or comparing fractions). For example, to calculate 3/5 + 1/6, we’d need to find the common denominator by calculating the lowest common multiple of 5 and 6 (30). We can then convert the fractions to 18/30 + 5/30 = 23/30.

Lowest common multiple practice questions

1) What is the lowest common multiple of 8 and 10?

2) Write all the common multiples of 3 and 8 that are less than 50.

3) What is the lowest common multiple of 100 and 50?

4) Write all the common multiples of 4 and 6 that are less than 60.

5) What is the lowest common multiple of 1000 and 650?


Related Articles

Primary Maths Dictionary for Kids and Parents [Free Download]: A Guide To The Mathematical Terms Your Child Will Be Taught In EYFS, KS1, And KS2

What Is A Square Number: Explained For Primary School Parents And Kids

What is BIDMAS: Explained For Primary Parents