Number Wizard is a great app for preschoolers and elementary schoolers. It is a math app that goes from counting to arithmetic to times tables.
There are four problem types:
Counting - Uses animals (with sounds) and stars.
Counting Problems - Addition, subtraction or both. Animals (with sounds) and stars.
Arithmetic Problems - Addition, subtraction, multiplication and division.
Times Tables - You specify which times table to use.
There are three play modes:
Flash Card - Gives you the answer.
Practice - Solve problems without keeping score.
Keep Score - Tracks your score. The wizard lets you know when you have a new high streak or high score.