Negative Prefixes:
* In- (often changes to "im-" before "p" or "b", to "ir-" before "r" or "l")
* Un-
* Non-
* Dis-
* A- (usually before words starting with "c", "k", "g", "h")
Applying to "Exact":
* Inexact: This is the most common and straightforward negative form of "exact", meaning not precise or accurate.
* Unexact: This is also possible, but less common. It implies a lack of precision or correctness.
* Nonexact: This is technically possible, but less natural in common usage.
* Disexact: This combination doesn't make sense in English.
* Aexact: This combination is not a valid word in English.
Therefore, the most common negative prefix for "exact" is "in-," forming the word "inexact."