Brain Test Level 42 Answer
Reading the equations on screen and trying to work out which one produces the biggest result. The equations are decoration.
The puzzle
What is the largest possible number?
The answer
999. The equations on screen are a distraction, so just enter the biggest three digit number.
What most people try first
Reading the equations on screen and trying to work out which one produces the biggest result.
Why that is the answer
The equations are decoration. Nothing asks you to solve them, and solving them leads nowhere. What the level gives you is an input box of a fixed width, so the real question is how large a number that box can hold. Three digits means the answer is 999. The trap is assuming that a screen full of sums must be a sum you are meant to do.
If your level 42 looks different
Unico Studio shuffles level numbers between game versions and platforms, so the puzzle on your screen may carry a different number from the one here. If the question above is not the one you are looking at, the full levels 1 to 50 walkthrough lists every puzzle in this stretch by its question, which is easier to match than a number.