Mental Maths Lite App for iOS
'What is 7 x (4 + 9)?
Needed more than five seconds? This can be better! With Mental Maths you can playfully improve your mental calculation skills through various exercises. Image puzzles are an incentive to carry on practicing.
Mental Maths Lite provides exercises on addition, division, square numbers and Roman numerals, giving you an idea of the numerous features provided by Mental Maths.'
This is a free app