Here is Fish World for Kids, an educational app for 3-6 years old kids, with which your kid studies as he or she play.
During the fishing time, there are simultaneously various questions for kids, e.g. how many fishes there are in water/How many fishes swam away/ how many fishes are left, etc. Of course, you need help him or her to finish these questions.
In the app, we provide you 12 levels totally. Your kid has to play these levels one by one, more difficult in later levels. By the way, there are 3 scenes in-built.