A few problems with how the game functions:
On some levels with fractions, either the question or answer bubbles can contain raw TeX markup, such as \frac\[1]\[4]. This is typically readable for those familiar with the language, but needless to say, it's not the most user-friendly way to be presented with the numbers. In the answer bubbles, these raw strings can take enough space that it shrinks the already-thin font too small to make out any of the numbers in the fraction whatsoever, which leads to an unplayable question.
Some "number sentence" questions get their signs mixed up. For example, there was one that read "? x 60 = 58" where the correct answer it wanted was 3480, as though it presented a multiplication problem when it really meant to ask for division. In most cases, it's obvious to see it as a wrong sign since there's no answer choice even remote close to what it would be going the other way. Still annoying.
For multiplation and division problems, some results have a precise answer that goes to 2 decimal digits of precision, but the answer choices are invariably limited to one decimal digit, leading to imprecise answers. Sure, you can find the one that's closest, but I remember one that asked "-7/22 x 3.3 = ?", with answer choices of -1.0, -1.1, -1.2, and -1.3. As it turns out, the equation results in exactly -1.05, dead center between two choices, so in order to solve it to the game's satisfaction, now we have to be aware of the game's canonical ROUNDING ALGORITHM: in case of a tie, does it round up? Down? Toward zero (which is different in the case of negative numbers, as this one was)? Away from zero? Toward the even digit? The game doesn't present any visible indication, so dinging a player for a wrong answer simply because they picked a different rounding algorithm (but still got the correct underlying result) is completely unjustified. On a side note, the game does appear to prefer "round away from zero", in case any other players are in a situation like this and are looking for clues to arrive at a single, unambiguous answer.