# Prime Factors

Many resources are available online for studying the prime factor decomposition of a number.

From CIMT  there are Interactive Exercises on Prime factors and on Highest Common Factor and Lowest Common Multiple.

From Spencer Riley’s TeacherLed the Prime Factor Tree resource provides a very attractive prime factor tree showing the prime factor decomposition for any number from 2 to 99.

From the National Library of Virtual Manipulatives comes this Factor Tree Resource.

Note the choice of Computer or User which means the user can select a number to decompose into prime factors.
By choosing two trees, the highest common factor (referred to as the greatest common factor) and lowest common multiple can be found.
Once both factor trees are complete the prime factors can be dragged to the given Venn diagram and the HCF and LCM checked.

A companion blog to this on Mathematics Starters includes information on Alec McEachran’s Primitives application  which provides an excellent visualisation of  the prime factorisation of a number.

This WolframAlpha widget gives the prime factor decomposition and divisors of a number. The widget allows you to change the displayed number.

Factorization by Stephen Von Worley

For two stunning vizualisations try Stephen Von Worley’s data visualization on factorization and Jeffrey Ventrella’s Composite Number Tree.

Jeffrey Ventrella’s Composite Number Tree

….and for a little fun try Manga High’s Sigma Prime!
(For further details on Manga High and student comments see this recent post.)

By Colleen Young Posted in Number

## 9 comments on “Prime Factors”

1. That is a good. I am planning that myself. I am planning a future project on this. Please tell me if you are interested to collaborate.

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• We should certainly keep each other posted!
Are my students younger than yours? They are 11 to 18 – and I’m aware of lots of little brothers and sisters too!

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• I actually have stopped teaching 7 years ago. I am currently on teacher training and curriculum development. We train teachers on teaching strategies and pedagogy and my specialization is on the integration of ICT, free software in particular, in teaching math.

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• I forgot. It’s not really 7 years, since I worked part-time teaching Grade 11 students since 2010. By the way, just a reminder, you are the host of the Math and Multimedia Carnival July edition. Posting date is July 11. Please confirm if you are available.

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• Yes indeed – July Carnival here!

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2. They surely are. By the way, are you developing Wolfram Alpha Widgets?

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• So far I have just created a few widgets to learn about them myself.
I have been thinking about putting together some sort of reference material on WolframAlpha for students.

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3. I hope they are useful Guillermo.

These have all worked well at school on the interactive whiteboard.

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4. Thanks for the links Colleen.

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