Neolara - it seems to me that dragonbox teaches the method for solving algebraic equations without teaching any understanding of what you're actually doing. However, my DCs have only been playing it for a short time, so maybe I'm judging it prematurely. I agree it's addictive though.
You could get books on non-verbal reasoning and/or verbal reasoning. There are probably apps you can download too. If you disregard their association with 11+ exams, they're actually good fun for kids who enjoy puzzles.