This app offers over 80 probability math puzzles in three levels.
I've included a math parser so that you can type equations as
answers: if the answer is 0.49^2 for example you can enter 0.49^2
or 0.49*0.49 without having to work out the multiplication
yourself. Some of the puzzles are very challenging even for people
who have studied college-level probability -- try answering them
all! If you get stuck there's a hint at the bottom of each page and
you can always skip puzzles (and return to them later) by swiping
horizontally. Have fun!