Pretty good
It's a nice little game which is Indeed a challenge for the mind. It reminds me of that "Total people in the house" game in "Brain Age". Although this game was a bit too hard for me (not 100% sure where I stand with the rest of newgrounds in mathematical prowess but...).
I liked the neonish effects against the black background, it really brings out the colors. However, the game seemed to take itself too seriously with the siren noises and the futuristic box and tube, it is just math after all. I'd suggest trying a calmer theme for things like this.
I also noticed that there was no music, which was probably a good call on your part as that may have distracted the player's concentration. But again, the siren noises were a bit over the top.
So in a nutshell, it's a simple yet hard game that while it has great graphics, is a little overboard on the seriousness.