Calculating voltage, current and resistance in electrical networks is a skill that most high school students have to learn. There are only a few rules, but it needs a lot of practicing to become familiar with complex resistor networks.
This program brings many exercises to help you to reach a high level of expertise in solving resistor networks:
+ 4 main subjects: - series and parallel - Ohm's law - power and energy - heavy circuits
+ different levels: from very simple 1 to extremely complex 5
+ scores are visible and saved
+ there is always a helping screen available

Try it out. It'll be fun.