Mathical Vol.1 (http://stusapps.com/mathical/) is now available at the Mac App Store. Developed by primary school teachers to target key skills, it’s a 5-in-1 compilation of games for primary and elementary aged children to practice mental calculation skills.
Mathical games all have customizable and increasing levels of difficulty depending on the age or ability of the child. Each game was created with continual play testing by children.
The skills the games encourage are: multiplication facts, division facts, times tables, addition and subtraction, inverse operations, place value, ordering decimals, and fractions of shapes. Mathical Vol. 1 costs US$1.99 and requires Mac OS X 10.5 or higher.