There is a easy trick for the brain age of 20 and its pretty simple,
HIT THE GUIDE BUTTON at all daily challenges,then it pauses you're game,
You can pause you're game whenever you want at any daily test.
But it doesn't work if you are going for the A+ achievement.
(Some test you can pause 4 A+but not all,like the daily tests)
i hope this helps got my 2 achievements verry quick this way