I suggest making satisfied equations green (and maybe unsatisfied ones red) as you go, rather than just at the end. There are a lot of equations that are ×1 or ÷1, which is less interesting than it could be. Fractions could be fun.
I got a puzzle with one equation already solved, and only intersecting with one other, so it wasn't actually doing anything. I can't see an identifier to specify which one it is, but it has 11 - 7 = 4 vertically on the left side.
I got a puzzle with one equation already solved, and only intersecting with one other, so it wasn't actually doing anything. I can't see an identifier to specify which one it is, but it has 11 - 7 = 4 vertically on the left side.
The difficulty seems to plateau pretty quickly.