exact(value)
IF POSSIBLE, the result will be rendered as an exact value - either a rational or a surd. Exact values which are rationals will be rendered as improper fractions. If you require a mixed number/fraction, use the mixed(value) function.
exact(1/2+1/3) = 5/6
exact(5sr8/4*3sr12/6) = 5sr6/2
Surds are always shown in the numerator. On the Global Parameters dialog, you can choose to show only prime surds.
With prime surds turned on
exact(5sr8/4*3sr12/6) = 5sr2sr3/2