This is a very interesting Japanese test.
It is widely known that our brain gets older and doesn’t always correspond to our actual age and it is likely to get older quicker if we don’t train it.
Of course, there are lots of other factors that influence its ageing like, for example, stress and bad habits (smoking).

First, you will see numbers which you should remember. Then, you’ll see circles that conceal these numbers.
Click on the circles in ascending order to uncover the numbers ( you have to remember these numbers which is from low to high and thier positions)
With every correct answer you’ll get an additional number as you proceed. Every time you fail, one number will be removed. Every time you play this game, you have to pass 10 levels. You will see the level in the corner on your left hand. When the level reaches 0 ( means game over), it will appear the result automatically, it will show how old is your brain. If you get 60 scores, that means your brain is as old as a 60 year old man's brain hhaha 
Put your results in the comments.
Very first time I tried I got 56 :$ and the second – 27 :)) hehe not bad with my age
Have fun and Good luck