Download X Challenge, Mental Math APK v2.2

Free download X Challenge, Mental Math APK for Android, PC. Latest version is 2.2, update at May 17, 2016

X Challenge, Mental Math version 2.2 is only one variant.

It's the year 2025, a race of super intelligent X aliens, challenges the human race's knowledge, experimental secret prototype droids are humanity's last chance of survival. The prototypes take the...