Forever Adding

Forever adding is a mindfuck math game. You just need to answer the question about adding math with right or wrong in a little of time. But, not like other math, in this game your 9 + 5 is not 14, but 4. And there some random position like button that usually switch between right and wrong when you start the game or random position of number's spawner that makes player hard to adapt the game.
This is not math, this is game. You will not be smarter if you play this game, the only one you get the same as study is only stress because you cannot make a big Highscore.

So, can (not) you add?

Cheer's

Note:
Credit for music:
Show Your Moves - Kevin MacLeod (incompetech.com)
Relent - Kevin MacLeod (incompetech.com)