Sometime a math item may seem confusing and/or too easy or hard for students. In some cases students may get an answer that was not an option, which might offer a hint that something was off in their calculations.
While we always welcome your observations and will gladly check for errors, the question may be in fact one that is quite easy or difficult, and does a good job of separating students at the lowest or highest end of the ability distribution from their peers performing above/below them. For example, students who have a very high math ability, on average, might get a very difficult question correct more often, on average, compared to students with lower math ability who have less and less chance to get the question correct as you move down the ability distribution.
When we construct the math benchmarks, they must have “reach” across the math ability spectrum from low to high, with particular reach into the middle-lower end because they are designed to screen students for risk. This is the reason why there are just a few math items that are very difficult and many more items that are of average or below average difficulty. We “clump” items in the latter region of the ability spectrum so that the test more accurately can screen for students at risk of not meeting grade-level expectations.
Rewording questions for clarity is one consideration, and we welcome your observations.