Fully updated post here (August 2015).
Perhaps time to remind everyone who enjoys these mental arithmetic games that there are plenty available they can still enjoy all year round. From Manga High a multi-player option is available on Sundae Times which tests multiplication from 1×1 to 15×15 – play other students from round the world!
Note the comment from Shane Hill below, for 4 to 10 year olds. Shane Hill, the creator of World Maths Day has provided Core Skills for 4 to 10 year olds, this can be played on PC or tablet and is available free all year round. (also for Windows and iPad instructions here).
Sum Sense from Oswego City School District. for example is a little different – arrange the given numbers to give a correct statement. If you like this game note that Sum Sense games are available for other operations, scroll down to the bottom of this collection.
I have been looking at Sumdog again recently, 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 so I thought I would try that this week with Year 10 as one of our many Enrichment Week activities. See the Teachers’ page.