Addictive!
This is a brilliant way to develop theory knowledge and prepare for the G5 theory exam. I used this together with Belinda Byers' Grade 5 theory workbook (on Amazon). The app gives you instant feedback and you can check the correct answer if you get stuck (helping you learn as you go along). The leaderboard helps you focus on what areas need the most work and watching your scores improve is very motivational (or even addictive!). I kept going until I had 100% on each section and then found past G5 papers much easier than before. Thoroughly recommended for all ages.