Irritating. I paid for it on my Nexus sometime back, but keep getting a -504 error when trying to upgrade. Just for the heck of it, I purchased a copy for my cell phone, to see if it had the same problem. It does. The older version was nice, but the upgrades are worthless. I'll unsubscribe both versions, and find a better math drill package.
Stop bugging me with - "Rate us!"
Great mind game
Helpful :) Good for practice but hope that you can include instructions on how to solve it...
A good challenge
▶ new chapter "Mixed 2"
▶ performance improvements and finer animations
▶ more supported display sizes