Complex sentence: The later do not produce results that are quite as accurate, but they can be explained and understood more easily, and lead to a simple approximation, accurate to within 1 minute of time, that can be evaluated with a calculator.
Split into simpler sentences: The later do not produce results that are quite as accurate, but they can be explained and understood more easily. Moreover, they lead to a simple approximation, accurate to within 1 minute of time, that can be evaluated with a calculator.