Mental Calculation is a fun app that includes specific math trainings. Whatever is your level or age it helps you to improve and progress in this area by practicing. Good for your brain!
Try the app for free with unlimited number of quiz and if you want to progress further and use all functionalities, you should get the Full Version to enable additional trainings and options.

Do your best, beat your high-score and win medals… bronze, silver, gold or reach the ultime price: the Genius Einstein badge which is a real challenge to reach! Choose the operation you want: addition, subtraction, multiplication, division or combine any of those. The light blue arrow indicates where you stand in this race. Useful App for schoolchildren who will learn with fun.

Get trained. With few minutes of exercise every day you will see improvements.

Trainings features and options includes:

basic operations (+, -, x, /)
multiplication tables training (1 to 20)
power calculation of numbers from 1 to 100
5 level of difficulties
adjustable time limit or no timer option
right answer displayed if you fail
history of your results, best score and prices you have won