# Sumdog – practise with those directed numbers….

….and other arithmetic skills.

Sumdog provides free numeracy games at 10 different levels. For a great way to practice adding and subtracting with negative numbers, play these games at level 10.  There is a complete list of topics at each level here. Students can choose from several games.

I like the way that the various skill levels can be restricted; the site is aimed at students aged 6 to 14 (having said that some of my Year 11 (age 15-16) students looked like they were rather enjoying themselves recently) so I want my secondary age students to practise the skills at the upper end of the age range and have currently restricted them all to levels 8, 9 and 10. It is possible to set up competitions which I have done very successfully with Year 10 as one of our many Enrichment Week activities. See the Teachers’ page, also the help section for teachers.

Sumdog are creating a library of videos to help teachers get the most out of Sumdog.

I have written some Instructions for students on the companion Mathematics blog for students.

You can choose to play as a guest or sign up (free) so you can save your scores and see how you improve over time. The games are all completely free to use as are several other features for teachers.

You can follow the Sumdog blog for all the latest features.

# Numbers in love with themsleves!

Watch the video from Numberphile to learn why 153 is in love with itself!

Numberphile launched their first video appropriately on 11th November 2011.

The Numberphile site which has a series of videos from Brady Haran has been added to the Videos collection in this Evernote notebook.

Another recent addition to this collection is PatrickJMT’s – Just Maths Tutorials – an extensive collection for students.

Note that there are suggested collections of videos to direct students to on the videos page of Mathematics For Students.

# 1000 Problems

The 1000 Problems site is an excellent collection of resources organised into collections on Number, Algebra, Shape and Space and Statistics. Within each category problems are organised by age and key words and a clear description are given for each problem. For each problem a file can be downloaded which includes the solution.

I have been working on Surds with one of my classes recently, looking at the Extension problems on Number I can see there is a problem on ‘Friendly Surds’ which would make a good starter to review the work we have been doing and extend to generalise – what conditions do we need for surds to be ‘friendly’?

For other Starter ideas see the companion blog Mathematics – a variety of resources to start and end lessons.

# Last Lessons ….

In the UK schools are finishing for the summer, some have already completed school for the year.

What to do for those last lessons?

No videos – though I could make an exception for the counting chimps, a video I was introduced to by Alex Bellos at the SSAT conference which he included in his session and shows the astonishing recall of a chimp – compare the human!

Some Mathematical games and puzzles perhaps? There are plenty to choose from.
Maybe….

# 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.

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

# Order of Operations

There are several resources to help demonstrate the correct order of operations in a calculation.

From the always relaible CIMT, one of their interactive sections gives examples and exercises.

A game from mathFROG allows students to practice against the clock.

..or try this game from Math Playground.

Finally an applet from Aplusmath.com.

# Fun Facts

WolframAlpha have now launched Fun Facts on Twitter. Note that you can read these facts even if you are not a Twitter user.
WolframAlpha have written on this in their own blog.

Now here’s an impressive fact from WolframAlpha on just how popular WordPress is:

On the subject of Mathematics Fun Facts – a reminder of these sites mentioned in earlier posts.

Mudd Math Fun Facts

Tanya Khovanova’s Number Gossip

Amazing Number Facts from Madras College.

# 2011

A new year resolution – more frequent posts.

I can make use of The DailyPost, and the community of other bloggers with similiar goals, to help me along the way.

So to 2011 – I feel an easy post coming here! Tanya Khovanova’s Number Gossip site caused interest when I blogged about it earlier. Using it to generate a few facts about 2011, we see that 2011 is deficient, odd,odious, prime and square-free! These terms are all explained on the Number Gossip site.

The Mathematical Association of America has a post on 2011 on its NumberADay blog.