five Free Apps for Brain Power

Luminosity Brain Trainer

Luminosity helps you improve your recall and learn more efficiently. This app uses clinically proven tools designed by neurosciences to clarify and speed up your thinking power, improve your problem-solving and better your concentration and memory.
 (iTunes, free)
https://itunes.apple.com/app/lumosity-brain-trainer/id338945375?mt=8

Mind Power 

We wouldn't play mind games with you, but this app will. It's got almost 20 different puzzles and 200 levels of difficulty to help you flex your brain biceps.
 (Google Play, free)
https://play.google.com/store/apps/details?id=com.oxothuk.worldpuzzle&feature=related_apps#?t=W251bGwsMSwxLDEwOSwiY29tLm94b3RodWsud29ybGRwdXp6bGUiXQ

Math Vs. Brain

How many years has it been since you did cross multiplication? Us, too. That's why we love Math vs. Brain, a free app that keeps you sharp. More than just math problems, this app is a math brainteaser game in which you compete to collect stars.

 (iTunes, free)
https://itunes.apple.com/gb/app/math-vs.-brain/id431484894?mt=8

My Personal Memory Trainer

This targeted training program works your spatial and working memoir, focus and other concentration skills. They've also recently added N-back, a continuous performance task that's proven to increase your fluid intelligence. In fact, it was mentioned in Wired's article on software that makes you smarter.

(Google Play, free)
https://play.google.com/store/apps/details?id=org.urbian.android.games.memorytrainer&feature=search_result#?t=W251bGwsMSwxLDEsIm9yZy51cmJpYW4uYW5kcm9pZC5nYW1lcy5tZW1vcnl0cmFpbmVyIl0.

Clockwork Brain

Named one of the 500 best apps in the world by The London Times, this offering from Total Eclipse features a series of mini games guided by Sprocket the Robot and created to test your cognitive abilities in logic, language, math and memory. And just to prove learning games don't have to be boring, all the artwork is hand-painted by artists with influences ranging from Victorian Steampunk to Mayan art.

 (iTunes, free)
https://itunes.apple.com/us/app/clockwork-brain-insanely-fun/id442745768?mt=8