ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

LCM. An easy method to work out the lowest common multiple in your maths exams.

Updated on May 4, 2011

The lowest common multiple of two or more numbers is the smallest number that is common to the multiples of the two or more numbers. The lowest common multiple is usually referred to as the LCM.

If you are trying to find the lowest common multiple all you need to do is write down the multiples of each of your numbers. Begin by writing down the first 5 multiples of each number, and continue adding more multiples if necessary until you come across the same multiple in each of your lists. This will be the LCM of your numbers.

Let’s take a look at some example on working out the LCM.

Example 1

Work out the lowest common multiple of 2 and 5.

First write down the first 5 multiples of 2 and 5.

The multiples of 2 are 2,4,6,8,10...

The multiples of 5 are 5,10,15,20,25...

As you can see the first multiple that you come across common to both lists is 10.

Example 2

Work out the lowest common multiple of 21 and 9.

First write down the first 5 multiples of 2 and 5.

The multiples of 2 are 2,4,6,8,10...

The multiples of 5 are 5,10,15,20,25...

As you can see the first multiple that you come across common to both lists is 10.

First write down the first 5 multiples of 21 and 9.

The multiples of 2 are 21,42,63,84,105...

The multiples of 5 are 9,18,27,36,45...

As you can see there is no multiple common to 21 and 9 in the first 5 multiples, so you need to write down some more multiples. Lets write down the next 5 multiples of each number.

21,42,63,84,105...,126,147,168,189,210...

9,18,27,36,45...54,63,72,81,90...

As you can see the LCM is 63 as this is the lowest multiple common to both times-tables.

Example 3

Find the lowest common multiple of 20,25 and 40.

This time let’s write down the first 10 multiples of each number.

20,40,60,80,100,120,140,160,180,200...

25,50,75,100,125,150,175,200,225,250...

40,80,120,160,200,240,280,320,360,400...

200 is in all of the 3 lists so 200 is the LCM of 20,25 and 400.

Make sure that you don’t mix up the LCM with the Highest Common Factor (also known as Greatest Common Divisor).

Comments

Submit a Comment

  • CyclingFitness profile image

    Liam Hallam 7 years ago from Nottingham UK

    Nice hub chap. Makes it all seem so straightforward. I used to love maths at school and when it's simplified and explained correctly it makes a whole world of difference.

  • Phillbert profile image

    Phillip Drayer Duncan 7 years ago from The Ozarks

    uggg I always hated math, but that was mostly because I had teachers that tended to go to fast without taking the time to dumb things down in to simple terms as you have here. Great job of explaining and making things simple to understand!

working

This website uses cookies

As a user in the EEA, your approval is needed on a few things. To provide a better website experience, hubpages.com uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: "https://hubpages.com/privacy-policy#gdpr"

Show Details
Necessary
HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
LoginThis is necessary to sign in to the HubPages Service.
Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
AkismetThis is used to detect comment spam. (Privacy Policy)
HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the googleapis.com or gstatic.com domains, for performance and efficiency reasons. (Privacy Policy)
Features
Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
MavenThis supports the Maven widget and search functionality. (Privacy Policy)
Marketing
Google AdSenseThis is an ad network. (Privacy Policy)
Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
Index ExchangeThis is an ad network. (Privacy Policy)
SovrnThis is an ad network. (Privacy Policy)
Facebook AdsThis is an ad network. (Privacy Policy)
Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
AppNexusThis is an ad network. (Privacy Policy)
OpenxThis is an ad network. (Privacy Policy)
Rubicon ProjectThis is an ad network. (Privacy Policy)
TripleLiftThis is an ad network. (Privacy Policy)
Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
Statistics
Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)