The tools help you learn and review operations with fractions. An exact result means the rational value was kept without rounding during the calculation; it does not guarantee that the data you entered, the units or your reading of the problem are correct.
Check the context
Before using a result, check what each quantity stands for. If you calculate 3/4 of 80 pieces, you get 60 pieces; if you typed 80 in a different unit, the tool cannot correct that interpretation by itself. For a physical measurement, consider the precision of the instrument and the rounding the work requires.
A decimal marked as approximate is not a substitute for the exact fraction when you need to keep calculating. Algebraic tools have domain restrictions, and a calculation rejected because of a technical limit does not prove that a problem has no solution.
Learning from the procedure
Read the steps, calculate again with a simple example and check the result with a different operation when possible. For a professional decision, also use the standards, instruments and human review that apply in that context.