How can round fractional results to the nearest 1/2, 1/4, 1/8, 1/12, 1/16, 1/32 etc.?

You can select to round fractions to the certain denominator in the Settings window. The app lets you round values to the nearest 1/2, 1/4, 1/8, 1/12, 1/16, 1/32, 1/64, 1/128, and 1/256.

If you do not need to round fractions, just select "-".