Short answer - In general, item writers try to isolate one issue that they want to evaluate so that it is easier to determine where the knowledge/cognitive brea

Short answer - In general, item writers try to isolate one issue that they want to evaluate so that it is easier to determine where the knowledge/cognitive breakdown occurs. Longer answer - According to test design principles, one would not use initial values that would lead to a potentially ambiguous rounding issue unless you were specifically testing the knowledge of rounding. In this particular case, there are much better ways to test knowledge of rounding than a two-step problem like the one your proposed.