Android version of the "How Much Pizza to order?
http://www.nummolt.com/obbl/howmuchpizza/index.html

"How much pizza...?" About adding fractions: Working with Improper fractions and Mixed fractions. The program build the problem, and you can solve filling the textboxes containing question marks. There's a tool that helps you find the common denominator.




Nummolt - OBBL Math Toys
http://www.nummolt.com/obbl/index.html

MathTools reference:
http://mathforum.org/mathtools/tool/186520/

Math 3 Equivalent fractions
Math 4 Equivalent fractions, Simplifying fractions, Adding fractions, Fractions <--> decimals
Math 5, 6, 7 Equivalent fractions, Simplifying fractions, Adding fractions, Multiplying fractions, Writing decimals, Fractions <--> decimals


For more difficult exercises on fractions, we recommend:
Mathcats: "Old Egyptian Fractions":