The cleanest input audit is to restate the problem using x₁, y₁, x₂ and y₂. If that sentence sounds wrong, correct the assignment before asking for midpoint.
Moving one endpoint by a given vector moves the midpoint by half that vector. Swapping endpoints changes nothing because coordinate averaging is symmetric. The pattern also provides a quick estimate of whether a revised result is plausible.
The midpoint bisects one segment. It should not be confused with a dataset mean unless the dataset consists exactly of the two endpoints considered coordinate by coordinate. The wording of the problem should decide which operation is appropriate.
The formula and result serve different readers: the formula shows what was done, and the rounded midpoint communicates scale. Keep both when the work needs review.
A screenshot is unnecessary when x₁, y₁, x₂ and y₂ and the shown formula are saved in plain text. Include the rounding rule if the reported midpoint is approximate.